drm/i915/display: Use int type for entry_setup_frames

entry_setup_frames variable is defined as u8. However, the
function call intel_psr_entry_setup_frames() can return
negative error code. There is a type mismatch here, so let's
switch to use int here as well.

Fixes: 2b981d57 ("drm/i915/display: Support PSR entry VSC packet to be transmitted one frame earlier")
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Reviewed-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231116090512.480373-1-mika.kahola@intel.com

drivers/gpu/drm/i915/display/intel_psr.c

@@ -1319,7 +1319,7 @@ static bool _psr_compute_config(struct intel_dp *intel_dp,
 {
 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
 	const struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
-	u8 entry_setup_frames;
+	int entry_setup_frames;
 
 	/*
 	 * Current PSR panels don't work reliably with VRR enabled