amdgcn: Remove -mlocal-symbol-id option

amdgcn: Remove -mlocal-symbol-id option

This patch removes the obsolete -mlocal-symbol-id option.  This was used to
control mangling of local symbol names in order to work around a ROCm runtime
bug, but that has not been needed in some time, and the mangling was removed
already.

gcc/ChangeLog:

	* config/gcn/gcn-hsa.h (CC1_SPEC): Delete.
	* config/gcn/gcn.opt (-mlocal-symbol-id): Delete.
	* config/gcn/mkoffload.c (main): Don't use -mlocal-symbol-id.

gcc/testsuite/ChangeLog:

	* gcc.dg/intermod-1.c: Don't use -mlocal-symbol-id.