rtc: mt6397: fix build on some 32bits platforms
rtc: mt6397: fix build on some 32bits platforms

On some !ARM 32bits platforms, the following compilation error happens
because of the division on a 64bits value in mtk_rtc_read_time():

drivers/built-in.o: In function `mtk_rtc_read_time':
rtc-mt6397.c:(.text+0x265d13f): undefined reference to `__divdi3'
rtc-mt6397.c:(.text+0x265d150): undefined reference to `__moddi3'

Use div_s64() as done in rtc_time64_to_tm() to solve that.

Reported-by: kbuild test robot <24f7fe9d205c8a9f6ade0c2894e14303ca16087f@intel.com>
Acked-by: Eddie Huang <bb4a162eb5fbb0ec0f3d6e8cf5d86f810e0b8b89@mediatek.com>
Signed-off-by: Alexandre Belloni <a7228e626ecf0022ac91fc1cd8db88e71d0e5e0e@free-electrons.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs