lsm: rename/rework ordered_lsm_parse() to lsm_order_parse()

lsm: rename/rework ordered_lsm_parse() to lsm_order_parse()

Rename ordered_lsm_parse() to lsm_order_parse() for the sake of
consistency with the other LSM initialization routines, and also
do some minor rework of the function.  Aside from some minor style
decisions, the majority of the rework involved shuffling the order
of the LSM_FLAG_LEGACY and LSM_ORDER_FIRST code so that the
LSM_FLAG_LEGACY checks are handled first; it is important to note
that this doesn't affect the order in which the LSMs are registered.

Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>