Allow hugetlbfs_t to be associated to /dev

Even if there is not FHS provision for this, systemd is using
/dev/hugepages to mount the hugetlbfs fs by default.

The needed file contexts are already present

policy/modules/kernel/filesystem.te

@@ -97,6 +97,7 @@ genfscon futexfs / gen_context(system_u:object_r:futexfs_t,s0)
 type hugetlbfs_t;
 fs_xattr_type(hugetlbfs_t)
 files_mountpoint(hugetlbfs_t)
+dev_associate(hugetlbfs_t)
 fs_use_trans hugetlbfs gen_context(system_u:object_r:hugetlbfs_t,s0);
 
 type ibmasmfs_t;