[SCSI] qla2xxx: Correct several PCI-EEH issues.

In addition to checking for potentially unnecessary iomem
readX()/writeX() operations, a pci_channel_io_perm_failure should
not trigger a full internal removal.  Found during additional
testing with pSeries blade systems.

Signed-off-by: Seokmann Ju <seokmann.ju@qlogic.com>
Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>