minix: convert minix to use the new mount api

Convert the minix filesystem to use the new mount API.

Tested using mount and remount on minix device.

Signed-off-by: Bill O'Donnell <bodonnel@redhat.com>
Link: https://lore.kernel.org/r/20240307163325.998723-1-bodonnel@redhat.com
Acked-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>