mtd: rawnand: meson: initialize clock register

Clock register must be also initialized during controller probing. If
this is not performed (for example by bootloader before) - controller
will not work.

Signed-off-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20231120064239.3304108-1-avkrasnov@salutedevices.com