[SCSI] qla2xxx: Handle unaligned sector writes during NVRAM/VPD updates.

Since both NVRAM and VPD regions of the flash reside on unaligned
sector boundaries, during update, the driver must perform a
read-modify-write operation to the composite NVRAM/VPD region.
This affects ISP25xx type boards only.

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