MIPS: FPU: Fix conflict of register usage

MIPS: FPU: Fix conflict of register usage

In _restore_fp_context/_restore_fp_context32, t0 is used for both
CP0_Status and CP1_FCSR. This is a mistake and cause FP exeception on
boot, so fix it.

Signed-off-by: Huacai Chen <[email protected]>
Tested-by: Aaro Koskinen <[email protected]>
Tested-by: Andreas Barth <[email protected]>
Cc: John Crispin <[email protected]>
Cc: Steven J. Hill <[email protected]>
Cc: Aurelien Jarno <[email protected]>
Cc: [email protected]
Cc: Fuxin Zhang <[email protected]>
Cc: Zhangjin Wu <[email protected]>
Patchwork: https://patchwork.linux-mips.org/patch/6507/
Signed-off-by: Ralf Baechle <[email protected]>