Replace M_SUF (fabs) with M_FABS

math-type-macros.h provides the macro M_FABS in order to reference
the correct fabs function for a specific type.
In most of the cases, M_FABS is identical to M_SUF (fabs), but that
may change in the future.

	* math/w_acos_template.c: Replace M_SUF (fabs) with M_FABS.
	* math/w_asin_template.c: Likewise.
	* math/w_atanh_template.c: Likewise.

Signed-off-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>