framebuffer: fix fbcmap.c kernel-doc warning

Fix kernel-doc warning in fbcmap.c:

Warning(drivers/video/fbcmap.c:92): No description found for parameter 'flags'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

drivers/video/fbcmap.c

@@ -80,6 +80,7 @@ static const struct fb_cmap default_16_colors = {
  *	@cmap: frame buffer colormap structure
  *	@len: length of @cmap
  *	@transp: boolean, 1 if there is transparency, 0 otherwise
+ *	@flags: flags for kmalloc memory allocation
  *
  *	Allocates memory for a colormap @cmap.  @len is the
  *	number of entries in the palette.