virtiofsd: Allow use "-o xattrmap" without "-o xattr"

When -o xattrmap is used, it will not work unless xattr is enabled.

This patch enables xattr when -o xattrmap is used.

Signed-off-by: Carlos Venegas <jose.carlos.venegas.munoz@intel.com>
Message-Id: <20210414201207.3612432-2-jose.carlos.venegas.munoz@intel.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Connor Kuehl <ckuehl@redhat.com>

tools/virtiofsd/passthrough_ll.c

@@ -3831,6 +3831,7 @@ int main(int argc, char *argv[])
     }
 
     if (lo.xattrmap) {
+        lo.xattr = 1;
         parse_xattrmap(&lo);
     }