rtc: pcf85363: add support for the quartz-load-femtofarads property

The quartz oscillator load capacitance of the PCF85263 and PCF85363 can
be adjusted to 6 pF, 7 pF (default) and 12.5 pF with the CL[1:0] bits in
the oscillator control register (address 25h).

Signed-off-by: Javier Carrasco <javier.carrasco@wolfvision.net>
Link: https://lore.kernel.org/r/20230215081815.3141776-3-javier.carrasco@wolfvision.net


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