connector: change connector's max message size

Change the maximum message size to 16k to allow transfers of VBE
data blocks from userspace.

Signed-off-by: Michal Januszewski <spock@gentoo.org>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>