drm/i915: Remove PLL asserts from .load_luts()

.load_luts() potentially runs from the vblank worker, and is
under a deadline to complete within the vblank. Thus we can't
do expesive stuff like talk to the Punit, etc.

To that end get rid of the assert_dsi_pll_enabled() call for
vlv/chv. We'll just have to trust that the PLL is already enabled
here.

And I don't think the normal assert_pll_enabled() really buys us
anything useful on gmch platforms either, so nuke that one too.
We don't have corresponding asserts in the ilk+ codepaths anyway
despite the hardware (IIRC) still requiring the clock to be
enabled when we access the LUT.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220929071521.26612-2-ville.syrjala@linux.intel.com


Acked-by: Jani Nikula <jani.nikula@intel.com>