MIPS: save/restore MSACSR register on context switch

I added a field for the MSACSR register in struct mips_fpu_struct, but
never actually made use of it... This is a clear bug. Save and restore
the MSACSR register along with the vector registers.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7300/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/asm-offsets.c b/arch/mips/kernel/asm-offsets.c
index 4bb5107..b1d84bd 100644
--- a/arch/mips/kernel/asm-offsets.c
+++ b/arch/mips/kernel/asm-offsets.c
@@ -234,6 +234,7 @@
 	       thread.fpu.fpr[31].val64[FPR_IDX(64, 0)]);
 
 	OFFSET(THREAD_FCR31, task_struct, thread.fpu.fcr31);
+	OFFSET(THREAD_MSA_CSR, task_struct, thread.fpu.msacsr);
 	BLANK();
 }