setcifsacl: fix up ACE mask handling

setcifsacl: fix up ACE mask handling

Change verify_ace_mask to just attempt to convert the argument to an
unsigned long first. If that fails, then try to treat it as a symbolic
mask string.

Also, clean up ace_mask_value. There's no need to walk the string
twice. Walk it once and turn the single-char mask checks into a switch
statement instead of if/else clauses.

Finally, fix the endianness of the resulting value. It must be in LE.

Signed-off-by: Jeff Layton <jlayton@samba.org>