gf-prepare-kernel: Fix detection of mountpoint
df reportes the mount to be devtmpfs in dev after changing the provider from busybox to the complete tool in core-base-utils.
(cherry picked from commit 765d4fc9)
df reportes the mount to be devtmpfs in dev after changing the provider from busybox to the complete tool in core-base-utils.
(cherry picked from commit 765d4fc9)