ARM: OMAP4+: Remove out of placed smp_wmb() in secondary wakeup code

The smp_wmb() here is out of placed and redundant. So remove it. It is
a left over of the pen_release cleanup mostly.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>

arch/arm/mach-omap2/omap-smp.c

@@ -186,8 +186,6 @@ static void __init wakeup_secondary(void)
 		__raw_writel(virt_to_phys(omap5_secondary_startup),
 						base + OMAP_AUX_CORE_BOOT_1);
 
-	smp_wmb();
-
 	/*
 	 * Send a 'sev' to wake the secondary core from WFE.
 	 * Drain the outstanding writes to memory