drm/i915: Program i830 DPLL FP register later

Follow the new i9xx DPLL FP register programming sequence
introduced in commit 62d66b21 ("drm/i915: Fold
i9xx_set_pll_dividers() into i9xx_enable_pll()") in the
i830 "power well" code as well. Just for consistency.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220321195006.775-2-ville.syrjala@linux.intel.com


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