[HIP] Fix rocm not found on rocm3.5

Currently rocm detector expects device library bitcodes named as *.bc
instead of *.amdgcn.bc. However in rocm3.5 the device library bitcodes
are named as *.amdgcn.bc, which causes rocm3.5 not detected.

This patch fixes that.

Differential Revision: https://reviews.llvm.org/D81713