drivers/rtc/rtc-s5m.c: terminate s5m_rtc_id array with empty element

Array of platform_device_id elements should be terminated with empty
element.

Fixes: 5bccae6e ("rtc: s5m-rtc: add real-time clock driver for s5m8767")
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>