megaraid_sas : move endianness conversion into caller of megasas_get_seq_num

Converting structure fields in place is always a bad idea, and in this case
by moving it into the only caller we also only have to do a single byte
swap as most fields of this structure are never used.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>