powerpc64le: Iterate over all object suffixes when appending -mfloat128
On powerpc64le, the compilation of the files related to float128 support
requires the option -mfloat128 to be passed to gcc. However, not all
possible object suffixes were covered in the Makefile. This patch uses
$(all-object-suffixes) in all remaining rules.
Tested for powerpc64le.
* sysdeps/powerpc/powerpc64le/Makefile: Use $(all-object-suffixes)
to iterate over all possible object suffixes. Add a comment
explaining the use of sysdep-CFLAGS instead of CFLAGS.