staging: media: omap4iss: Fixes NULL comparison

This patch fixes the checkpatch issue:

CHECK: Comparison to NULL could be written

Signed-off-by: Amarjargal Gundjalam <amarjargal.gundjalam@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/media/omap4iss/iss_resizer.c b/drivers/staging/media/omap4iss/iss_resizer.c
index 5030cf3..8035e01 100644
--- a/drivers/staging/media/omap4iss/iss_resizer.c
+++ b/drivers/staging/media/omap4iss/iss_resizer.c
@@ -274,7 +274,7 @@
 	resizer_enable(resizer, 0);
 
 	buffer = omap4iss_video_buffer_next(&resizer->video_out);
-	if (buffer == NULL)
+	if (!buffer)
 		return;
 
 	resizer_set_outaddr(resizer, buffer->iss_addr);
@@ -588,7 +588,7 @@
 	struct v4l2_mbus_framefmt *format;
 
 	format = __resizer_get_format(resizer, cfg, fmt->pad, fmt->which);
-	if (format == NULL)
+	if (!format)
 		return -EINVAL;
 
 	fmt->format = *format;
@@ -612,7 +612,7 @@
 	struct v4l2_mbus_framefmt *format;
 
 	format = __resizer_get_format(resizer, cfg, fmt->pad, fmt->which);
-	if (format == NULL)
+	if (!format)
 		return -EINVAL;
 
 	resizer_try_format(resizer, cfg, fmt->pad, &fmt->format, fmt->which);