drm/i915: Use min() instead of hand rolling it

Most places in the vblank code use min() to clamp scanline
counters below vtotal. But we missed one in the gen3/4
pixel counter based codepath.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230404175431.23064-3-ville.syrjala@linux.intel.com


Reviewed-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>