sha/asm/sha512p8-ppc.pl: optimize epilogue.

Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7643)

(cherry picked from commit 6b956fe77b8aeb899ef7bdfa147a00bda51b804a)

crypto/sha/asm/sha512p8-ppc.pl

@@ -286,24 +286,17 @@ $code.=<<___		if ($SZ==8);
 	stvx_u		$G,$x30,$ctx
 ___
 $code.=<<___;
-	li		r10,`$LOCALS+15`
+	addi		$offload,$sp,`$LOCALS+15`
 	mtlr		$lrsave
-	li		r11,`$LOCALS+31`
 	mtspr		256,$vrsave
-	lvx		v24,r10,$sp		# ABI says so
-	addi		r10,r10,32
-	lvx		v25,r11,$sp
-	addi		r11,r11,32
-	lvx		v26,r10,$sp
-	addi		r10,r10,32
-	lvx		v27,r11,$sp
-	addi		r11,r11,32
-	lvx		v28,r10,$sp
-	addi		r10,r10,32
-	lvx		v29,r11,$sp
-	addi		r11,r11,32
-	lvx		v30,r10,$sp
-	lvx		v31,r11,$sp
+	lvx		v24,$x00,$offload	# ABI says so
+	lvx		v25,$x10,$offload
+	lvx		v26,$x20,$offload
+	lvx		v27,$x30,$offload
+	lvx		v28,$x40,$offload
+	lvx		v29,$x50,$offload
+	lvx		v30,$x60,$offload
+	lvx		v31,$x70,$offload
 	$POP		r26,`$FRAME-6*$SIZE_T`($sp)
 	$POP		r27,`$FRAME-5*$SIZE_T`($sp)
 	$POP		r28,`$FRAME-4*$SIZE_T`($sp)