Fix up 'c-c++-common/goacc/firstprivate-mappings-1.c' for C, non-LP64

Follow-up to recent og10 commit a70b5b1aa8b3d32f6728dbfcfc00b0cff8c5219d
"OpenMP 5.0: Implement relaxation of implicit map vs. existing device
mappings".

	gcc/testsuite/
	* c-c++-common/goacc/firstprivate-mappings-1.c: Fix up for C,
	non-LP64.
2 files changed