mfd: adp5585: Enable oscillator during probe

mfd: adp5585: Enable oscillator during probe

Make sure to enable the oscillator in the top device. This will allow to
not control this in the child PWM device as that would not work with
future support for keyboard matrix where the oscillator needs to be
always enabled (and so cannot be disabled by disabling PWM).

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Acked-by: Uwe Kleine-König <ukleinek@kernel.org>
Link: https://lore.kernel.org/r/20250701-dev-adp5589-fw-v7-3-b1fcfe9e9826@analog.com
Signed-off-by: Lee Jones <lee@kernel.org>