mips: rs870e: stop exporting local functions

These four functions are exported, but don't have any users, and no
prototypes, which now causes warnings:

drivers/platform/mips/rs780e-acpi.c:35:6: error: no previous prototype for 'pm_iowrite' [-Werror=missing-prototypes]
drivers/platform/mips/rs780e-acpi.c:41:4: error: no previous prototype for 'pm_ioread' [-Werror=missing-prototypes]
drivers/platform/mips/rs780e-acpi.c:47:6: error: no previous prototype for 'pm2_iowrite' [-Werror=missing-prototypes]
drivers/platform/mips/rs780e-acpi.c:53:4: error: no previous prototype for 'pm2_ioread' [-Werror=missing-prototypes]

Link: https://lkml.kernel.org/r/20231204115710.2247097-5-arnd@kernel.orgSigned-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Stephen Rothwell <sfr@rothwell.id.au>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/platform/mips/rs780e-acpi.c

@@ -32,29 +32,25 @@ static u8 pmio_read_index(u16 index, u8 reg)
 	return inb(index + 1);
 }
 
-void pm_iowrite(u8 reg, u8 value)
+static void pm_iowrite(u8 reg, u8 value)
 {
 	pmio_write_index(PM_INDEX, reg, value);
 }
-EXPORT_SYMBOL(pm_iowrite);
 
-u8 pm_ioread(u8 reg)
+static u8 pm_ioread(u8 reg)
 {
 	return pmio_read_index(PM_INDEX, reg);
 }
-EXPORT_SYMBOL(pm_ioread);
 
-void pm2_iowrite(u8 reg, u8 value)
+static void pm2_iowrite(u8 reg, u8 value)
 {
 	pmio_write_index(PM2_INDEX, reg, value);
 }
-EXPORT_SYMBOL(pm2_iowrite);
 
-u8 pm2_ioread(u8 reg)
+static u8 pm2_ioread(u8 reg)
 {
 	return pmio_read_index(PM2_INDEX, reg);
 }
-EXPORT_SYMBOL(pm2_ioread);
 
 static void acpi_hw_clear_status(void)
 {