rtc: isl1208: Drop enum isl1208_id and split isl1208_configs[]

Drop enum isl1208_id and split the array isl1208_configs[] as individual
variables, and make lines shorter by referring to e.g. &config_isl1219
instead of &isl1208_configs[TYPE_ISL1219].

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/20230623140948.384762-9-biju.das.jz@bp.renesas.com


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