libgfortran: Skip integer-kind=16 check for amdgcn

libgfortran: Skip integer-kind=16 check for amdgcn

libgfortran/ChangeLog:

	PR target/96306
	* configure.ac: Add LIBGOMP_CHECKED_INT_KINDS and
	LIBGOMP_CHECKED_REAL_KINDS and use it for to skip
	integer kind=16 checks for amdgcn.
	* Makefile.am (kinds.h, selected_int_kind.inc,
	selected_real_kind.inc): Pass them on.
	* mk-kinds-h.sh: Takes to-be-check kinds as argument.
	* mk-sik-inc.sh: Likewise.
	* mk-srk-inc.sh: Likewise.
	* Makefile.in: Regenerate.
	* configure: Regenerate.