rtc: isl1208: Simplify probe()

Simplify the probe() by replacing of_device_get_match_data() and
i2c_match_id() by i2c_get_match_data() as we have similar I2C
and DT-based matching table.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230710114747.106496-1-biju.das.jz@bp.renesas.com


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>