rtc: ds1347: fix value written to century register

In `ds1347_set_time()`, the wrong value is being written to the
`DS1347_CENTURY_REG` register. It needs to be converted to BCD. Fix
it.

Fixes: 147dae76dbb9 ("rtc: ds1347: handle century register")
Cc: <[e-mail]> # v5.5+
Signed-off-by: Ian Abbott <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexandre Belloni <[e-mail]>

drivers/rtc/rtc-ds1347.c

···
 		return err;
 
 	century = (dt->tm_year / 100) + 19;
-	err = regmap_write(map, DS1347_CENTURY_REG, century);
+	err = regmap_write(map, DS1347_CENTURY_REG, bin2bcd(century));
 	if (err)
 		return err;