drm/i915: correct the pitch check for NV12 framebuffer

framebuffer for NV12 requires the pitch to the multiplier of 4, instead
of the width. This patch corrects it.

For instance, a 480p video, whose width and pitch are 854 and 896
respectively, is excluded for NV12 plane so far.

Changes since v1:
    - Removed check for NV12 buffer dimensions since additional checks
      are done for viewport size in intel_sprite.c
Signed-off-by: Dongseong Hwang <dongseong.hwang@intel.com>
Signed-off-by: P Raviraj Sitaram <raviraj.p.sitaram@intel.com>
Cc: Chandra Konduru <chandra.konduru@intel.com>
Cc: Vidya Srinivas <vidya.srinivas@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1545208152-22658-1-git-send-email-raviraj.p.sitaram@intel.com

drivers/gpu/drm/i915/intel_display.c

@@ -14710,14 +14710,6 @@ static int intel_framebuffer_init(struct intel_framebuffer *intel_fb,
 
 	drm_helper_mode_fill_fb_struct(&dev_priv->drm, fb, mode_cmd);
 
-	if (fb->format->format == DRM_FORMAT_NV12 &&
-	    (fb->width < SKL_MIN_YUV_420_SRC_W ||
-	     fb->height < SKL_MIN_YUV_420_SRC_H ||
-	     (fb->width % 4) != 0 || (fb->height % 4) != 0)) {
-		DRM_DEBUG_KMS("src dimensions not correct for NV12\n");
-		goto err;
-	}
-
 	for (i = 0; i < fb->format->num_planes; i++) {
 		u32 stride_alignment;