omap: Fix sev instruction usage for multi-omap

Otherwise we get the following error with omap3_defconfig and CONFIG_SMP:

Error: selected processor does not support `sev'

Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>

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

@@ -102,8 +102,7 @@ static void __init wakeup_secondary(void)
 	 * Send a 'sev' to wake the secondary core from WFE.
 	 * Drain the outstanding writes to memory
 	 */
-	dsb();
-	set_event();
+	dsb_sev();
 	mb();
 }