powerpc/40x: Don't save CR in SPRN_SPRG_SCRATCH6

We have r12 available, use it to keep CR around and don't
save it in SPRN_SPRG_SCRATCH6.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/019f314a98c107c4ca46e46c1cf402e9a44114a7.1590079969.git.christophe.leroy@csgroup.eu

arch/powerpc/kernel/head_40x.S

@@ -254,9 +254,8 @@ _ENTRY(saved_ksp_limit)
 	mtspr	SPRN_SPRG_SCRATCH1, r11
 	mtspr	SPRN_SPRG_SCRATCH3, r12
 	mtspr	SPRN_SPRG_SCRATCH4, r9
-	mfcr	r11
+	mfcr	r12
 	mfspr	r9, SPRN_PID
-	mtspr	SPRN_SPRG_SCRATCH6, r11
 	mtspr	SPRN_SPRG_SCRATCH5, r9
 	mfspr	r10, SPRN_DEAR		/* Get faulting address */
 
@@ -323,9 +322,8 @@ _ENTRY(saved_ksp_limit)
 	 * and call the heavyweights to help us out.
 	 */
 	mfspr	r9, SPRN_SPRG_SCRATCH5
-	mfspr	r11, SPRN_SPRG_SCRATCH6
 	mtspr	SPRN_PID, r9
-	mtcr	r11
+	mtcr	r12
 	mfspr	r9, SPRN_SPRG_SCRATCH4
 	mfspr	r12, SPRN_SPRG_SCRATCH3
 	mfspr	r11, SPRN_SPRG_SCRATCH1
@@ -341,9 +339,8 @@ _ENTRY(saved_ksp_limit)
 	mtspr	SPRN_SPRG_SCRATCH1, r11
 	mtspr	SPRN_SPRG_SCRATCH3, r12
 	mtspr	SPRN_SPRG_SCRATCH4, r9
-	mfcr	r11
+	mfcr	r12
 	mfspr	r9, SPRN_PID
-	mtspr	SPRN_SPRG_SCRATCH6, r11
 	mtspr	SPRN_SPRG_SCRATCH5, r9
 	mfspr	r10, SPRN_SRR0		/* Get faulting address */
 
@@ -410,9 +407,8 @@ _ENTRY(saved_ksp_limit)
 	 * and call the heavyweights to help us out.
 	 */
 	mfspr	r9, SPRN_SPRG_SCRATCH5
-	mfspr	r11, SPRN_SPRG_SCRATCH6
 	mtspr	SPRN_PID, r9
-	mtcr	r11
+	mtcr	r12
 	mfspr	r9, SPRN_SPRG_SCRATCH4
 	mfspr	r12, SPRN_SPRG_SCRATCH3
 	mfspr	r11, SPRN_SPRG_SCRATCH1
@@ -556,9 +552,8 @@ finish_tlb_load:
 	/* Done...restore registers and get out of here.
 	*/
 	mfspr	r9, SPRN_SPRG_SCRATCH5
-	mfspr	r11, SPRN_SPRG_SCRATCH6
 	mtspr	SPRN_PID, r9
-	mtcr	r11
+	mtcr	r12
 	mfspr	r9, SPRN_SPRG_SCRATCH4
 	mfspr	r12, SPRN_SPRG_SCRATCH3
 	mfspr	r11, SPRN_SPRG_SCRATCH1