watchdog:marvell_gti: Update missing MODULE_LICENSE

commit 8fa5ef29976832672f8ec10a7a39cb02328e8ee3 from
git@git.assembla.com:cavium/WindRiver.linux.git

Update the missing MODULE_LICENSE. Missing MODULE_LICENSE prevents the
driver to be loaded as a kernel module.

Change-Id: Ib32c55194c3b0327f3e023c15624fd4589f9b610
Signed-off-by: George Cherian <george.cherian@marvell.com>
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/105597
Tested-by: sa_ip-sw-jenkins <sa_ip-sw-jenkins@marvell.com>
Reviewed-by: Bharat Bhushan <bbhushan2@marvell.com>
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/105741
Reviewed-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>