MIPS: OCTEON: Remove some unused files.

These FPA related files are not used anywhere in the kernel.  Remove
them.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3892/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>