[SCSI] qla2xxx: Correct ISP24xx soft-reset handling.

A driver must wait 100us before attempting an MMIO operation
to the RISC after a soft-reset has been initiated.  A
similar delay was needed with earlier ISPs.

Note: a PCI config-space read is used to flush the MMIO
write to the ISP, since the ISP's state machines are unable
to respond to any MMIO read during the reset process.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>