drm/i915/cx0: Move definition of Cx0 PHY functions earlier

drm/i915/cx0: Move definition of Cx0 PHY functions earlier

Move the definitions of the
  intel_c10pll_calc_port_clock()
  intel_c20_get_dp_rate()
  intel_c20_get_hdmi_rate()
  is_hdmi_frl()
  is_dp2()
  intel_get_c20_custom_width()
functions earlier to avoid the forward declarations.

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/20251117104602.2363671-7-mika.kahola@intel.com