MIPS: kernel: cps-vec: Use ta0-ta3 pseudo-registers for 64-bit

MIPS: kernel: cps-vec: Use ta0-ta3 pseudo-registers for 64-bit

The cps-vec code assumes O32 ABI and uses t4-t7 in quite a few places. This
breaks the build on 64-bit. As a result of which, use the pseudo-registers
ta0-ta3 to make the code compatible with 64-bit.

Cc: <stable@vger.kernel.org> # 3.16+
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10589/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>