Staging: atomisp: fix an uninitialized variable bug

There are some error paths in atomisp_css_frame_allocate() which don't
initialize "res" so it could lead us to try release random memory.

Fixes: a49d2536 ("staging/atomisp: Add support for the Intel IPU v2")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/media/atomisp/pci/atomisp2/atomisp_cmd.c

@@ -4722,7 +4722,7 @@ static int
 atomisp_v4l2_framebuffer_to_css_frame(const struct v4l2_framebuffer *arg,
 					 struct atomisp_css_frame **result)
 {
-	struct atomisp_css_frame *res;
+	struct atomisp_css_frame *res = NULL;
 	unsigned int padded_width;
 	enum atomisp_css_frame_format sh_format;
 	char *tmp_buf = NULL;