mkinitfs fails if feature list is empty

Mkinitfs only works is the feature list is not empty. In case an empty feature list is passed, the following errors occur

cp: cannot create regular file '/tmp/mkinitfs.VAMw3T/lib/modules/4.4.52-2-armada/': No such file or directory
cp: cannot create regular file '/tmp/mkinitfs.VAMw3T/lib/modules/4.4.52-2-armada/': No such file or directory
depmod: ERROR: could not open directory /tmp/mkinitfs.VAMw3T/lib/modules/4.4.52-2-armada: No such file or directory
depmod: FATAL: could not search modules: No such file or directory
find: /tmp/mkinitfs.VAMw3T/lib/modules: No such file or directory
modinfo: ERROR: missing module or filename.

The attached patch fixes this issue:

0002-mkinitfs-fix-empty-feature-list.patch