Fast GeLU using built-in function

[asroy]

Without built-in function:

With built-in function (this PR):

[zjing14]

CI failed with the following warning:

[2023-02-22T20:58:28.811Z] /home/jenkins/workspace/mposable_kernel_builtin_fastgelu/include/ck/tensor_operation/gpu/element/unary_element_wise_operation.hpp:15:29: warning: identifier 'ocml_native_recip_f32' is reserved because it starts with '' [-Wreserved-identifier]

[2023-02-22T20:58:28.811Z] extern "C" device float __ocml_native_recip_f32(float);

[asroy]

CI failed with the following warning:

[2023-02-22T20:58:28.811Z] /home/jenkins/workspace/mposable_kernel_builtin_fastgelu/include/ck/tensor_operation/gpu/element/unary_element_wise_operation.hpp:15:29: warning: identifier 'ocml_native_recip_f32' is reserved because it starts with '' [-Wreserved-identifier]

[2023-02-22T20:58:28.811Z] extern "C" device float __ocml_native_recip_f32(float);

It actually failed because of some function is missing, which I'm trying to fix

The "xtern "C" device float __ocml_native_recip_f32(float)" is a warning