dt-bindings: mfd: ti,twl: Add clock provider properties

Since these devices provide clock outputs, add the corresponding
property.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230916100515.1650336-3-andreas@kemnade.info


Signed-off-by: Lee Jones <lee@kernel.org>