[media] media: Use single quotes to quote entity names

Instead of double quotes, use single quotes to quote entity names. Using
single quotes is consistent with the English language and is also in line
with the practices across the kernel.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>