powerpc/8xx: Simplify INVALIDATE_ADJACENT_PAGES_CPU15

We now have r11 available as a scratch register so
INVALIDATE_ADJACENT_PAGES_CPU15() can be simplified.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bdafd651b4ac3a851fd09249f5f3699c50da29f2.1606231483.git.christophe.leroy@csgroup.eu

arch/powerpc/kernel/head_8xx.S

@@ -180,14 +180,13 @@ SystemCall:
  */
 
 #ifdef CONFIG_8xx_CPU15
-#define INVALIDATE_ADJACENT_PAGES_CPU15(addr)	\
-	addi	addr, addr, PAGE_SIZE;	\
-	tlbie	addr;			\
-	addi	addr, addr, -(PAGE_SIZE << 1);	\
-	tlbie	addr;			\
-	addi	addr, addr, PAGE_SIZE
+#define INVALIDATE_ADJACENT_PAGES_CPU15(addr, tmp)	\
+	addi	tmp, addr, PAGE_SIZE;	\
+	tlbie	tmp;			\
+	addi	tmp, addr, -PAGE_SIZE;	\
+	tlbie	tmp
 #else
-#define INVALIDATE_ADJACENT_PAGES_CPU15(addr)
+#define INVALIDATE_ADJACENT_PAGES_CPU15(addr, tmp)
 #endif
 
 InstructionTLBMiss:
@@ -198,7 +197,7 @@ InstructionTLBMiss:
 	 * kernel page tables.
 	 */
 	mfspr	r10, SPRN_SRR0	/* Get effective address of fault */
-	INVALIDATE_ADJACENT_PAGES_CPU15(r10)
+	INVALIDATE_ADJACENT_PAGES_CPU15(r10, r11)
 	mtspr	SPRN_MD_EPN, r10
 #ifdef CONFIG_MODULES
 	mfcr	r11