drm/i915: Support for higher DSI clk

For MIPI panels requiring higher DSI clk, values needs to be added
in lfsr_converts table for getting the correct values of pll ctrl
and dividor values which gets programmed in cck regs, otherwise DSI
PLL does not get locked leading to no display on the MIPI panel.

Signed-off-by: Gaurav K Singh <gaurav.k.singh@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>