drm/i915/dmc: use intel uncore functions for forcewake register access

Move away from I915_READ_FW() and I915_WRITE_FW() and switch to using
intel_uncore_read_fw() and intel_uncore_write_fw(), respectively.

No functional changes.
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200123140004.14136-1-jani.nikula@intel.com

drivers/gpu/drm/i915/intel_csr.c

@@ -315,7 +315,8 @@ void intel_csr_load_program(struct drm_i915_private *dev_priv)
 	preempt_disable();
 
 	for (i = 0; i < fw_size; i++)
-		I915_WRITE_FW(CSR_PROGRAM(i), payload[i]);
+		intel_uncore_write_fw(&dev_priv->uncore, CSR_PROGRAM(i),
+				      payload[i]);
 
 	preempt_enable();