drm/i915: Remove redundant on stack dpll_hw_state from bxt_get_dpll()

Just store the stuff directly into crtc_state->dpll_hw_state rather
than to a temp and copying the whole thing over.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190207173230.22368-6-ville.syrjala@linux.intel.com


Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>