Start cleaning up libm.

We have two copies of fenv.h for every architecture, one of which
isn't used. We also have unused makefiles and files for architectures
we don't support.

This patch removes all the obviously useless files.

Bug: http://code.google.com/p/android/issues/detail?id=38196
Change-Id: I1919b6621ba513aa24aa947a34815bc51191487c
50 files changed