greybus: core: add MODULE uevent var for all control devices

The new ctrl device under interface is missing a MODULE uevent var,
add it.

Testing Done:
cat 'uevent' from ctrl device.
$ cat 1-3.3.ctrl/uevent
DEVTYPE=greybus_control
BUS=1
MODULE=3
INTERFACE=3
GREYBUS_ID=fffe0001/ffee0011

Signed-off-by: Sandeep Patil <sspatil@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>