target: Fix MAINTENANCE_IN service action CDB checks to use lower 5 bits

This patch fixes the MAINTENANCE_IN service action type checks to only
look at the proper lower 5 bits of cdb byte 1.  This addresses the case
where MI_REPORT_TARGET_PGS w/ extended header using the upper three bits of
cdb byte 1 was not processed correctly in transport_generic_cmd_sequencer,
as well as the three cases for standby, unavailable, and transition ALUA
primary access state checks.

Also add MAINTENANCE_IN to the excluded list in transport_generic_prepare_cdb()
to prevent the PARAMETER DATA FORMAT bits from being cleared.

Cc: Hannes Reinecke <hare@suse.de>
Cc: Rob Evers <revers@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>