ARM: Factor out common code from cpu_proc_fin()

All implementations of cpu_proc_fin() start by disabling interrupts
and then flush caches.  Rather than have every processors proc_fin()
implementation do this, move it out into generic code - and move the
cache flush past setup_mm_for_reboot() (so it can benefit from having
caches still enabled.)

This allows cpu_proc_fin() to become independent of the L1/L2 cache
types, and eventually move the L2 cache flushing into the L2 support
code.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/proc-arm740.S

@@ -36,15 +36,11 @@ ENTRY(cpu_arm740_switch_mm)
  * cpu_arm740_proc_fin()
  */
 ENTRY(cpu_arm740_proc_fin)
-	stmfd	sp!, {lr}
-	mov	ip, #PSR_F_BIT | PSR_I_BIT | SVC_MODE
-	msr	cpsr_c, ip
 	mrc	p15, 0, r0, c1, c0, 0
 	bic	r0, r0, #0x3f000000		@ bank/f/lock/s
 	bic	r0, r0, #0x0000000c		@ w-buffer/cache
 	mcr	p15, 0, r0, c1, c0, 0		@ disable caches
-	mcr	p15, 0, r0, c7, c0, 0		@ invalidate cache
-	ldmfd	sp!, {pc}
+	mov	pc, lr
 
 /*
  * cpu_arm740_reset(loc)