Support storing 7 additional file flags in tmpfs:

UF_SYSTEM, UF_SPARSE, UF_OFFLINE, UF_REPARSE, UF_ARCHIVE, UF_READONLY,
and UF_HIDDEN.

Sort the file flags tmpfs supports alphabetically.  tmpfs now
supports the same flags as UFS, with the exception of SF_SNAPSHOT.

Reported by:	bdrewery, antoine
Sponsored by:	Spectra Logic