cifs: Unconditionally copy mount options to superblock info

Previously mount options were copied and updated in the cifs_sb_info
struct only when CONFIG_CIFS_DFS_UPCALL was enabled.  Making this
information generally available allows us to remove a number of ifdefs,
extra function params, and temporary variables.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Sean Finney <seanius@seanius.net>
Signed-off-by: Steve French <sfrench@us.ibm.com>