Use libm_alias_float for coldfire.

Continuing the preparation for additional _FloatN / _FloatNx function
aliases, this patch makes coldfire libm function implementations use
libm_alias_float to define function aliases.

Untested, given the currently broken state of GCC for coldfire.

	* sysdeps/m68k/coldfire/fpu/s_fabsf.c: Include
	<libm-alias-float.h>.
	(fabsf): Define using libm_alias_float.
	* sysdeps/m68k/coldfire/fpu/s_lrintf.c: Include
	<libm-alias-float.h>.
	(lrintf): Define using libm_alias_float.
	* sysdeps/m68k/coldfire/fpu/s_rintf.c: Include
	<libm-alias-float.h>.
	(rintf): Define using libm_alias_float.