MIPS: ip22-gio: Make ip22_gio_set_64bit() and ip22_gio_init() static

These functions are used in only one file.
Made them static to fix the following build error:

arch/mips/sgi-ip22/ip22-gio.c:249:6: error: no previous prototype for ‘ip22_gio_set_64bit’ [-Werror=missing-prototypes]
arch/mips/sgi-ip22/ip22-gio.c:398:12: error: no previous prototype for ‘ip22_gio_init’ [-Werror=missing-prototypes]
Reported-by: k2ci <kernel-bot@kylinos.cn>
Signed-off-by: Genjian Zhang <zhanggenjian@kylinos.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/sgi-ip22/ip22-gio.c

@@ -246,7 +246,7 @@ void gio_set_master(struct gio_device *dev)
 }
 EXPORT_SYMBOL_GPL(gio_set_master);
 
-void ip22_gio_set_64bit(int slotno)
+static void ip22_gio_set_64bit(int slotno)
 {
 	u32 tmp = sgimc->giopar;
 
@@ -395,7 +395,7 @@ static struct resource gio_bus_resource = {
 	.flags = IORESOURCE_MEM,
 };
 
-int __init ip22_gio_init(void)
+static int __init ip22_gio_init(void)
 {
 	unsigned int pbdma __maybe_unused;
 	int ret;