drm/i915: Fix cursor visibility check with negative coordinates

When the cursor x coordinate is exactly -cursor_width, the cursor is
invisible. And obviously the same holds for the y coordinate and
cursor_height.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -6937,7 +6937,7 @@ static void intel_crtc_update_cursor(struct drm_crtc *crtc,
 		base = 0;
 
 	if (x < 0) {
-		if (x + intel_crtc->cursor_width < 0)
+		if (x + intel_crtc->cursor_width <= 0)
 			base = 0;
 
 		pos |= CURSOR_POS_SIGN << CURSOR_X_SHIFT;
@@ -6946,7 +6946,7 @@ static void intel_crtc_update_cursor(struct drm_crtc *crtc,
 	pos |= x << CURSOR_X_SHIFT;
 
 	if (y < 0) {
-		if (y + intel_crtc->cursor_height < 0)
+		if (y + intel_crtc->cursor_height <= 0)
 			base = 0;
 
 		pos |= CURSOR_POS_SIGN << CURSOR_Y_SHIFT;