[Libomptarget] Remove dependency on the DeviceRTL from the GPU plugins

The GPU plugins have a dependency on the device libraries. Sometimes we
cannot build the device libraries because the user does not have a valid
`clang` to use or it was explicitly disabled. Currently this leads to a
transitive failure because we cannot meet this dependency. This patch
simply removes that dependency.

Fixes #60457

Reviewed By: tianshilei1992

Differential Revision: https://reviews.llvm.org/D143196

openmp/libomptarget/plugins-nextgen/amdgpu/CMakeLists.txt

@@ -90,7 +90,6 @@ add_llvm_library(omptarget.rtl.amdgpu.nextgen SHARED
 
   NO_INSTALL_RPATH
 )
-add_dependencies(omptarget.rtl.amdgpu.nextgen omptarget.devicertl.amdgpu)
 
 target_include_directories(
   omptarget.rtl.amdgpu.nextgen

openmp/libomptarget/plugins-nextgen/cuda/CMakeLists.txt

@@ -51,7 +51,6 @@ else()
   target_include_directories(omptarget.rtl.cuda.nextgen PRIVATE ../../plugins/cuda/dynamic_cuda)
   target_sources(omptarget.rtl.cuda.nextgen PRIVATE ../../plugins/cuda/dynamic_cuda/cuda.cpp)
 endif()
-add_dependencies(omptarget.rtl.cuda.nextgen omptarget.devicertl.nvptx)
 
 # Define debug prefix. TODO: This should be automatized in the Debug.h but it
 # requires changing the original plugins.

openmp/libomptarget/plugins/amdgpu/CMakeLists.txt

@@ -90,7 +90,6 @@ add_llvm_library(omptarget.rtl.amdgpu SHARED
 
   NO_INSTALL_RPATH
 )
-add_dependencies(omptarget.rtl.amdgpu omptarget.devicertl.amdgpu)
 
 target_include_directories(
   omptarget.rtl.amdgpu

openmp/libomptarget/plugins/cuda/CMakeLists.txt

@@ -50,7 +50,6 @@ else()
   target_include_directories(omptarget.rtl.cuda PRIVATE dynamic_cuda)
   target_sources(omptarget.rtl.cuda PRIVATE dynamic_cuda/cuda.cpp)
 endif()
-add_dependencies(omptarget.rtl.cuda omptarget.devicertl.nvptx)
 
 # Define the suffix for the runtime messaging dumps.
 target_compile_definitions(omptarget.rtl.cuda PRIVATE TARGET_NAME="CUDA")