libc & libm: use hard float

Summary: This change does not require a global float abi change, or multi lib changes. This shouldn't affect anything using assembly that greatly, meaning it might be good to readdress performance differences between some c and assembly routines.

Test Plan: Stability on all devices should be confirmed as well as math and bionic performance.

Reviewers: Mustaavalkosta, michyprima, randall.rushing, rlasalle15, synergy

Reviewed By: synergy

Differential Revision: http://review.codefirex.com/D68