media: mt9m114: Use aptina-PLL helper to get PLL values

media: mt9m114: Use aptina-PLL helper to get PLL values

Before this change the driver used hardcoded PLL m, n and p values to
achieve a 48MHz pixclock when used with an external clock with a frequency
of 24 MHz.

Use aptina_pll_calculate() to allow the driver to work with different
external clock frequencies. The m, n, and p values will be unchanged
with a 24 MHz extclk and this has also been tested with a 19.2 MHz
clock where m gets increased from 32 to 40.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans de Goede <johannes.goede@oss.qualcomm.com>
[Sakari Ailus: Fix capitalisation of "MHz".]
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>