arm: omap2: Fix warning in force_emif_self_refresh

The function declaration for force_emif_self_refresh takes no parameters
but does not specify this, only the prototype in the headers do.  As
clang will warn about this, correct it.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/mach-omap2/emif-common.c b/arch/arm/mach-omap2/emif-common.c
index a6a97af..9daaeef 100644
--- a/arch/arm/mach-omap2/emif-common.c
+++ b/arch/arm/mach-omap2/emif-common.c
@@ -40,7 +40,7 @@
 	readl(&emif->emif_pwr_mgmt_ctrl);
 }
 
-void force_emif_self_refresh()
+void force_emif_self_refresh(void)
 {
 	set_lpmode_selfrefresh(EMIF1_BASE);
 	if (!is_dra72x())