MIPS: SMTC: Support for Multi-threaded FPUs

Signed-off-by: Steven J. Hill <sjhill@mips.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3603/


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