Fix m68k bits/math-inline.h macro namespace (bug 22035).

Fix m68k bits/math-inline.h macro namespace (bug 22035).

As shown by build bot failures
<https://sourceware.org/ml/libc-testresults/2017-q3/msg00349.html> the
m68k bits/mathinline.h is not namespace-clean: it fails to compile if
the user has defined macros f or l before it is included, because of
expansions of those arguments to __inline_functions.  This patch
changes the __inline_functions definitions to take not the suffix but
a macro that concatenates it with the function name, to avoid the
spurious macro expansions.

Tested for m68k with build-many-glibcs.py.

	[BZ #22035]
	* sysdeps/m68k/m680x0/fpu/bits/mathinline.h (__inline_functions):
	Define to take a second argument that is a macro that
	concatentates a suffix, not the suffix itself.
	(__CONCAT_d): New macro.
	(__CONCAT_f): Likewise.
	(__CONCAT_l): Likewise.