Move FP_ATTRIB to floating_point_abi.h, use in binding.h

The floating point ABI attribute needs to be set on all
bionic-based Android library functions (theoretically only
if the function has floating point arguments or return
values, but it does not hurt to have it for all functions).

Move all duplicate definitions of FP_ATTRIB into a central
place and use FP_ATTRIB in the macros of binding.h to make
sure generated wrapper functions work correctly.

Signed-off-by: Thomas Perl <thomas.perl@jollamobile.com>
Merge pull request #87 from thp/fp-attrib-central

Move FP_ATTRIB to floating_point_abi.h, use in binding.h