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 <chenhc@lemote.com>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Tested-by: Andreas Barth <aba@ayous.org>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/6507/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/r4k_fpu.S

@@ -146,7 +146,7 @@ LEAF(_save_fp_context32)
  *  - cp1 status/control register
  */
 LEAF(_restore_fp_context)
-	EX	lw t0, SC_FPC_CSR(a0)
+	EX	lw t1, SC_FPC_CSR(a0)
 
 #if defined(CONFIG_64BIT) || defined(CONFIG_CPU_MIPS32_R2)
 	.set	push
@@ -191,7 +191,7 @@ LEAF(_restore_fp_context)
 	EX	ldc1 $f26, SC_FPREGS+208(a0)
 	EX	ldc1 $f28, SC_FPREGS+224(a0)
 	EX	ldc1 $f30, SC_FPREGS+240(a0)
-	ctc1	t0, fcr31
+	ctc1	t1, fcr31
 	jr	ra
 	 li	v0, 0					# success
 	END(_restore_fp_context)
@@ -199,7 +199,7 @@ LEAF(_restore_fp_context)
 #ifdef CONFIG_MIPS32_COMPAT
 LEAF(_restore_fp_context32)
 	/* Restore an o32 sigcontext.  */
-	EX	lw t0, SC32_FPC_CSR(a0)
+	EX	lw t1, SC32_FPC_CSR(a0)
 
 	mfc0	t0, CP0_STATUS
 	sll	t0, t0, 5
@@ -239,7 +239,7 @@ LEAF(_restore_fp_context32)
 	EX	ldc1 $f26, SC32_FPREGS+208(a0)
 	EX	ldc1 $f28, SC32_FPREGS+224(a0)
 	EX	ldc1 $f30, SC32_FPREGS+240(a0)
-	ctc1	t0, fcr31
+	ctc1	t1, fcr31
 	jr	ra
 	 li	v0, 0					# success
 	END(_restore_fp_context32)