OMAP3: PM: Fix the MMU on sequence in the asm code

Add necessary barriers after enabling MMU. Also use the sane way to
load pc and jump to it instead of executing ldma first up.
Signed-off-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: NKevin Hilman <khilman@ti.com>

arch/arm/mach-omap2/sleep34xx.S

@@ -617,12 +617,17 @@ usettbr0:
 	ldr	r2, cache_pred_disable_mask
 	and	r4, r2
 	mcr	p15, 0, r4, c1, c0, 0
+	dsb
+	isb
+	ldr     r0, =restoremmu_on
+	bx      r0
 
 /*
  * ==============================
  * == Exit point from OFF mode ==
  * ==============================
  */
+restoremmu_on:
 	ldmfd	sp!, {r0-r12, pc}	@ restore regs and return