drm/i915/cx0: Determine Cx0 PLL port clock from PLL state

drm/i915/cx0: Determine Cx0 PLL port clock from PLL state

The port clock is tracked in the PLL state, so there is no need to pass
it separately to __intel_cx0pll_enable(). Drop the port clock function
param accordingly.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://lore.kernel.org/r/20251117104602.2363671-13-mika.kahola@intel.com