Revert 'Use more ARRAY_SIZE.' for mkoffload

Revert 'Use more ARRAY_SIZE.' for mkoffload

Revert commit r13-472-gca32b29ec3e92dcf8dda5c2501d0baf9dd1cb09d partially;
namely for {gcn,nvptx}/mkoffload.cc, only.

The patch changed 'sizeof(...)/sizeof(...[0])' to the 'ARRAY_SIZE' macro,
which is in principle a good idea – except that in the two mkoffload.cc,
the change happened inside a string that is used to generate plain C code.

With offlading to nvptx or gcn, the mkoffload genenates then the C file
and compilation of the latter fails with
"warning: implicit declaration of function 'ARRAY_SIZE'" followed by
"error: initializer element is not constant"

gcc/
	* config/gcn/mkoffload.cc (process_obj): Revert: Use ARRAY_SIZE.
	* config/nvptx/mkoffload.cc (process): Likewise.