drm/i915: pass dev_priv explicitly to DSPSURFLIVE

Avoid the implicit dev_priv local variable use, and pass dev_priv
explicitly to the DSPSURFLIVE register macro.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/bc252dee67718f729883da7d542c6435384683ae.1716469091.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>