amdgcn: update target-supports.exp

The backend can now vectorize more things.

gcc/testsuite/ChangeLog:

	* lib/target-supports.exp
	(check_effective_target_vect_call_copysignf): Add amdgcn.
	(check_effective_target_vect_call_sqrtf): Add amdgcn.
	(check_effective_target_vect_call_ceilf): Add amdgcn.
	(check_effective_target_vect_call_floor): Add amdgcn.
	(check_effective_target_vect_logical_reduc): Add amdgcn.