ARM: OMAP2+: make dra7xx_sha0_hwmod static

The dra7xx_sha0_hwmod object is not exported outside of
omap_hwmod_7xx_data. so make it static to avoid the
following warning:

arch/arm/mach-omap2/omap_hwmod_7xx_data.c:686:19: warning: symbol 'dra7xx_sha0_hwmod' was not declared. Should it be static?
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/omap_hwmod_7xx_data.c

@@ -683,7 +683,7 @@ static struct omap_hwmod_class dra7xx_sha0_hwmod_class = {
 	.sysc		= &dra7xx_sha0_sysc,
 };
 
-struct omap_hwmod dra7xx_sha0_hwmod = {
+static struct omap_hwmod dra7xx_sha0_hwmod = {
 	.name		= "sham",
 	.class		= &dra7xx_sha0_hwmod_class,
 	.clkdm_name	= "l4sec_clkdm",