ARM: omap2: make omap5_erratum_workaround_801819 static

Fix sparse warning:

arch/arm/mach-omap2/omap-smp.c:75:6: warning: symbol
'omap5_erratum_workaround_801819' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Ma Feng <mafeng.ma@huawei.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

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

@@ -72,7 +72,7 @@ void __iomem *omap4_get_scu_base(void)
 }
 
 #ifdef CONFIG_OMAP5_ERRATA_801819
-void omap5_erratum_workaround_801819(void)
+static void omap5_erratum_workaround_801819(void)
 {
 	u32 acr, revidr;
 	u32 acr_mask;