media: docs-rst: media: Don't use \small for V4L2_PIX_FMT_SRGGB10 documentation

There appears to be an issue in using \small in certain cases on Sphinx
1.4 and 1.5. Other format documents don't use \small either, remove it
from here as well.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

[mchehab@s-opensource.com: kept tabularcolumns - readjusted - and
 add a few blank lines for it to display better]
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>