[TFTRT]: Revert "Merge pull request #55655"

[meena-at-work]

[TFTRT]: Revert device placement changes as it causes
issues on graphs with nodes that are not runnable on
GPUs.

This reverts commit 0842ad1, reversing
changes made to dd89837.

CC: @bixia1 , @DEKHTIARJonathan @nluehr

[DEKHTIARJonathan]

@bixia1 please merge this PR ASAP to correct the bug previously mentioned over email.
Thanks

[meena-at-work]

this PR "assigns GPU:0" to be default device of the whole graph, which is perfectly fine as long as all OPs are compatible on GPU. In case the graph has ops that don't run on GPUs, tftrt conversion fails. This needs to be addressed.

2022-05-04 14:46:05.313250: W tensorflow/core/grappler/utils/graph_view.cc:836] No registered 'Const' OpKernel for GPU devices compatible with node {{node MultipleGridAnchorGenerator/assert_equal/Assert/Assert/data_4}}
     (OpKernel was found, but attributes didn't match) Requested Attributes: dtype=DT_STRING, value=Tensor<type: string shape: [] values: y (MultipleGridAnchorGenerator/add_23:0) = >, _device="/job:localhost/replica:0/task:0/device:GPU:0"
   .  Registered:  device='XLA_CPU_JIT'; dtype in [DT_FLOAT, DT_DOUBLE, DT_INT32, DT_UINT8, DT_INT16, 2189089607411394171, DT_COMPLEX128, DT_HALF, DT_UINT32, DT_UINT64, DT_STRING]
  device='XLA_GPU_JIT'; dtype in [DT_FLOAT, DT_DOUBLE, DT_INT32, DT_UINT8, DT_INT16, 2189089607411394171, DT_COMPLEX128, DT_HALF, DT_UINT32, DT_UINT64, DT_STRING]
  device='DEFAULT'; dtype in [DT_VARIANT]
  device='DEFAULT'; dtype in [DT_BOOL]
  device='DEFAULT'; dtype in [DT_QUINT16]
  device='DEFAULT'; dtype in [DT_QINT16]
  device='DEFAULT'; dtype in [DT_QINT32]
  device='DEFAULT'; dtype in [DT_QUINT8]
  device='DEFAULT'; dtype in [DT_QINT8]
  device='DEFAULT'; dtype in [DT_COMPLEX128]
  device='DEFAULT'; dtype in [DT_COMPLEX64]
  device='DEFAULT'; dtype in [DT_INT8]
  device='DEFAULT'; dtype in [DT_UINT8]
  device='DEFAULT'; dtype in [DT_INT16]
  device='DEFAULT'; dtype in [DT_UINT16]
  device='DEFAULT'; dtype in [DT_UINT32]
  device='DEFAULT'; dtype in [DT_INT64]
  device='DEFAULT'; dtype in [DT_UINT64]
  device='DEFAULT'; dtype in [DT_DOUBLE]
  device='DEFAULT'; dtype in [DT_FLOAT]
  device='DEFAULT'; dtype in [DT_BFLOAT16]
  device='DEFAULT'; dtype in [DT_HALF]
  device='DEFAULT'; dtype in [DT_INT32]
  device='XLA_CPU'; dtype in [DT_UINT8, DT_QUINT8, DT_UINT16, DT_INT8, DT_QINT8, 1081042544580029293, DT_DOUBLE, DT_COMPLEX64, DT_COMPLEX128, DT_BOOL, DT_BFLOAT16]
  device='XLA_GPU'; dtype in [DT_UINT8, DT_QUINT8, DT_UINT16, DT_INT8, DT_QINT8, 1081042544580029293, DT_DOUBLE, DT_COMPLEX64, DT_COMPLEX128, DT_BOOL, DT_BFLOAT16]
  device='GPU'; dtype in [DT_VARIANT]
  device='GPU'; dtype in [DT_BOOL]
  device='GPU'; dtype in [DT_COMPLEX128]
  device='GPU'; dtype in [DT_COMPLEX64]
  device='GPU'; dtype in [DT_UINT64]
  device='GPU'; dtype in [DT_INT64]
  device='GPU'; dtype in [DT_QINT32]
  device='GPU'; dtype in [DT_UINT32]
  device='GPU'; dtype in [DT_QUINT16]
  device='GPU'; dtype in [DT_QINT16]
  device='GPU'; dtype in [DT_INT16]
  device='GPU'; dtype in [DT_UINT16]
  device='GPU'; dtype in [DT_QINT8]
  device='GPU'; dtype in [DT_INT8]
  device='GPU'; dtype in [DT_UINT8]
  device='GPU'; dtype in [DT_DOUBLE]
  device='GPU'; dtype in [DT_FLOAT]
  device='GPU'; dtype in [DT_BFLOAT16]
  device='GPU'; dtype in [DT_HALF]
  device='CPU'