sparse report build warning as follows:
drivers/platform/mips/rs780e-acpi.c:72:6: warning:
 symbol 'acpi_registers_setup' was not declared. Should it be static?
And function acpi_registers_setup() is not used outside of this file,
so marks it static.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
        outl(inl(ACPI_GPE0_BLK), ACPI_GPE0_BLK);
 }
 
-void acpi_registers_setup(void)
+static void acpi_registers_setup(void)
 {
        u32 value;