tcg/ppc64: Only one call output register needed for 64 bit hosts

The second register is only needed for 32 bit hosts.

Cc: Vassili Karpov <av1474@comtv.ru>
Fine-with-me'd-by: Vassili Karpov <av1474@comtv.ru>
Signed-off-by: NStefan Weil <weil@mail.berlios.de>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

tcg/ppc64/tcg-target.c

@@ -130,7 +130,7 @@ static const int tcg_target_call_iarg_regs[] = {
     TCG_REG_R10
 };
 
-static const int tcg_target_call_oarg_regs[2] = {
+static const int tcg_target_call_oarg_regs[] = {
     TCG_REG_R3
 };