The request_t 'handle' member is 32-bits wide, hence use wrt_reg_dword().
Change the cast in the wrt_reg_byte() call to make it clear that a regular
pointer is casted to an __iomem pointer.

Note: 'pkt' points to I/O memory for the qlafx00 adapter family and to
coherent memory for all other adapter families.

This patch fixes the following Coverity complaint:

CID 358864 (#1 of 1): Reliance on integer endianness (INCOMPATIBLE_CAST)
incompatible_cast: Pointer &pkt->handle points to an object whose effective
type is unsigned int (32 bits, unsigned) but is dereferenced as a narrower
unsigned short (16 bits, unsigned). This may lead to unexpected results
depending on machine endianness.

Link: https://lore.kernel.org/r/20200629225454.22863-7-bvanassche@acm.org
Fixes: 8ae6d9c7 ("[SCSI] qla2xxx: Enhancements to support ISPFx00.")
Cc: Nilesh Javali <njavali@marvell.com>
Cc: Quinn Tran <qutran@marvell.com>
Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
Cc: Martin Wilck <mwilck@suse.com>
Cc: Roman Bolshakov <r.bolshakov@yadro.com>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>