media: ccs-pll: Fix comment on check against maximum PLL multiplier

The comment is about minimum PLL multiplier but the related check really
deals with the maximum PLL multiplier.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>