kernel: Rename USE_FP and USE_SSE symbols

Symbols now use the K_ prefix which is now standard for the
unified kernel. Legacy support for these symbols is retained
to allow existing applications to build successfully.

Change-Id: I3ff12c96f729b535eecc940502892cbaa52526b6
Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
13 files changed