rtc: mc146818-lib: fix signedness bug in mc146818_get_time()

The mc146818_get_time() function returns zero on success or negative
a error code on failure.  It needs to be type int.

Fixes: d35786b3 ("rtc: mc146818-lib: change return values of mc146818_get_time()")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220111071922.GE11243@kili

drivers/rtc/rtc-mc146818-lib.c

@@ -130,7 +130,7 @@ static void mc146818_get_time_callback(unsigned char seconds, void *param_in)
 	p->ctrl = CMOS_READ(RTC_CONTROL);
 }
 
-unsigned int mc146818_get_time(struct rtc_time *time)
+int mc146818_get_time(struct rtc_time *time)
 {
 	struct mc146818_get_time_callback_param p = {
 		.time = time

include/linux/mc146818rtc.h

@@ -124,7 +124,7 @@ struct cmos_rtc_board_info {
 #endif /* ARCH_RTC_LOCATION */
 
 bool mc146818_does_rtc_work(void);
-unsigned int mc146818_get_time(struct rtc_time *time);
+int mc146818_get_time(struct rtc_time *time);
 int mc146818_set_time(struct rtc_time *time);
 
 bool mc146818_avoid_UIP(void (*callback)(unsigned char seconds, void *param),