rtc: s3c: Use generic helper to get driver data

rtc: s3c: Use generic helper to get driver data

Replace of_match_node() with of_device_get_match_data(), which removes a
few lines of code from the driver.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
[backport of mainline commit 64704c92fd19c599f20433aae1372a7ccab79a57]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Change-Id: I9e3a1662233334925ca9ace34609468dc8bc0a14