scsi: qla2xxx: Introduce the be_id_t and le_id_t data types for FC src/dst IDs

Introduce the be_id_t and le_id_t data types for Fibre Channel source and
destination ID formats supported by the firmware instead of using an
uint8_t[3] array. Introduce functions for converting from and to the
port_id_t data types. This patch does not change the behavior of the
qla2xxx driver but improves source code readability and also allows the
compiler to verify the endianness of Fibre Channel IDs.

Cc: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Himanshu Madhani <hmadhani@marvell.com>
Reviewed-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>