powerpc/e500: Save SPEFCSR in flush_spe_to_thread()

giveup_spe() saves the SPE state which is protected by MSR[SPE].
However, modifying SPEFSCR does not trap when MSR[SPE]=0.
And since SPEFSCR is already saved/restored in _switch(),
not all the callers want to save SPEFSCR again.
Thus, saving SPEFSCR should not belong to giveup_spe().

This patch moves SPEFSCR saving to flush_spe_to_thread(),
and cleans up the caller that needs to save SPEFSCR accordingly.

Signed-off-by: Liu Yu <yu.liu@freescale.com>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 1a01414..f19d977 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -1387,10 +1387,7 @@
 	int code = 0;
 	int err;
 
-	preempt_disable();
-	if (regs->msr & MSR_SPE)
-		giveup_spe(current);
-	preempt_enable();
+	flush_spe_to_thread(current);
 
 	spefscr = current->thread.spefscr;
 	fpexc_mode = current->thread.fpexc_mode;