mfd: rk808: Re-add rk808-clkout to RK818

Fixes RK818 (e.g. on Pinephone Pro) to register its clock, without which
dependent devices (e.g. wifi/BT, via sdio-wifi-pwrseq) fail to probe.

This line was removed in commit 3633daac
("mfd: rk808: Permit having multiple PMIC instances"), but only from RK818.

Fixes: 3633daac ("mfd: rk808: Permit having multiple PMIC instances")
Signed-off-by: Tom Fitzhenry <tom@tom-fitzhenry.me.uk>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230102111147.2580861-1-tom@tom-fitzhenry.me.uk