soc/mediatek: Change rtc_bbpu_power_on to static function

BUG=b:388796896
TEST=compiled on kukui/asurada/cherry/corsola/geralt

Change-Id: Iea9a1aa5e19887513c537d0787f0434b51736c08
Signed-off-by: Yidi Lin <yidilin@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/86924
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/mediatek/common/rtc_mt6359p.c

@@ -283,7 +283,7 @@ err:
 }
 
 /* enable rtc bbpu */
-void rtc_bbpu_power_on(void)
+static void rtc_bbpu_power_on(void)
 {
 	u16 bbpu;
 	int ret;

src/soc/mediatek/mt8183/include/soc/rtc.h

@@ -80,7 +80,6 @@ enum {
 
 
 /* external API */
-void rtc_bbpu_power_on(void);
 int rtc_init(int recover);
 bool rtc_gpio_init(void);
 void rtc_boot(void);

src/soc/mediatek/mt8183/rtc.c

@@ -263,7 +263,7 @@ err:
 }
 
 /* enable rtc bbpu */
-void rtc_bbpu_power_on(void)
+static void rtc_bbpu_power_on(void)
 {
 	u16 bbpu;
 	int ret;

src/soc/mediatek/mt8186/include/soc/rtc.h

@@ -85,7 +85,6 @@ enum {
 
 
 /* external API */
-void rtc_bbpu_power_on(void);
 int rtc_init(int recover);
 bool rtc_gpio_init(void);
 void rtc_boot(void);

src/soc/mediatek/mt8186/rtc.c

@@ -301,7 +301,7 @@ err:
 }
 
 /* Enable RTC bbpu */
-void rtc_bbpu_power_on(void)
+static void rtc_bbpu_power_on(void)
 {
 	u16 bbpu;
 	int ret;

src/soc/mediatek/mt8188/include/soc/rtc.h

@@ -84,7 +84,6 @@ enum {
 
 void rtc_read(u16 addr, u16 *rdata);
 void rtc_write(u16 addr, u16 wdata);
-void rtc_bbpu_power_on(void);
 int rtc_init(int recover);
 bool rtc_gpio_init(void);
 void rtc_boot(void);

src/soc/mediatek/mt8192/include/soc/rtc.h

@@ -85,7 +85,6 @@ enum {
 
 void rtc_read(u16 addr, u16 *rdata);
 void rtc_write(u16 addr, u16 wdata);
-void rtc_bbpu_power_on(void);
 int rtc_init(int recover);
 bool rtc_gpio_init(void);
 void rtc_boot(void);

src/soc/mediatek/mt8195/include/soc/rtc.h

@@ -85,7 +85,6 @@ enum {
 
 void rtc_read(u16 addr, u16 *rdata);
 void rtc_write(u16 addr, u16 wdata);
-void rtc_bbpu_power_on(void);
 int rtc_init(int recover);
 bool rtc_gpio_init(void);
 void rtc_boot(void);