MIPS: RB532: Declare prom_setup_cmdline() and rb532_gpio_init() static

early_tlb_init() and rb532_gpio_init() were local to file but not declared
static, leading to error:

arch/mips/rb532/prom.c:49:13: error: no previous prototype for ‘prom_setup_cmdline’ [-Werror=missing-prototypes]
   49 | void __init prom_setup_cmdline(void)
      |             ^~~~~~~~~~~~~~~~~~
arch/mips/rb532/gpio.c:200:12: error: no previous prototype for ‘rb532_gpio_init’ [-Werror=missing-prototypes]
  200 | int __init rb532_gpio_init(void)
      |            ^~~~~~~~~~~~~~~
Signed-off-by: Yongzhen Zhang <zhangyongzhen@kylinos.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/rb532/gpio.c

@@ -197,7 +197,7 @@ void rb532_gpio_set_func(unsigned gpio)
 }
 EXPORT_SYMBOL(rb532_gpio_set_func);
 
-int __init rb532_gpio_init(void)
+static int __init rb532_gpio_init(void)
 {
 	struct resource *r;
 

arch/mips/rb532/prom.c

@@ -46,7 +46,7 @@ static inline unsigned long tag2ul(char *arg, const char *tag)
 	return simple_strtoul(num, 0, 10);
 }
 
-void __init prom_setup_cmdline(void)
+static void __init prom_setup_cmdline(void)
 {
 	static char cmd_line[COMMAND_LINE_SIZE] __initdata;
 	char *cp, *board;