PPC32: work around the fact that the PPC601 doesn't implement the MSR.RI bit

arch/ppc/kernel/entry.S

@@ -672,6 +672,10 @@ nonrecoverable:
 	mr	r12,r11		/* restart at exc_exit_restart */
 	blr
 3:	/* OK, we can't recover, kill this process */
+	/* but the 601 doesn't implement the RI bit, so assume it's OK */
+BEGIN_FTR_SECTION
+	blr
+END_FTR_SECTION_IFSET(CPU_FTR_601)
 	lwz	r3,TRAP(r1)
 	andi.	r0,r3,1
 	beq	4f

arch/ppc/kernel/head.S

@@ -832,7 +832,12 @@ fast_exception_return:
 
 /* aargh, a nonrecoverable interrupt, panic */
 /* aargh, we don't know which trap this is */
-3:	li	r10,0
+/* but the 601 doesn't implement the RI bit, so assume it's OK */
+3:
+BEGIN_FTR_SECTION
+	b	2b
+END_FTR_SECTION_IFSET(CPU_FTR_601)
+	li	r10,-1
 	stw	r10,TRAP(r11)
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	li	r10,MSR_KERNEL