powerpc: fix giveup_vsx to save registers correctly

giveup_vsx didn't save the FPU and VMX regsiters.  Change it to be
like giveup_fpr/altivec which save these registers.

Also update call sites where FPU and VMX are already saved to use the
original giveup_vsx (renamed to __giveup_vsx).

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 6f6810d..3e80aa3 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -452,7 +452,7 @@
 	 * contains valid data
 	 */
 	if (current->thread.used_vsr) {
-		flush_vsx_to_thread(current);
+		__giveup_vsx(current);
 		if (copy_vsx_to_user(&frame->mc_vsregs, current))
 			return 1;
 		msr |= MSR_VSX;