verify: enable header seed check for 100% write jobs

verify: enable header seed check for 100% write jobs

There are 3 modes where verify can be performed. write, read and
readwrite. The existing readwrite condition prohibits header seed check
for write or read workloads. For write workloads, there shouldn't be any
extra limitation that triggers header seed mismatch which cannot be
triggered with readwrite workloads. Hence modify this condition to only
disable verify header seed checks for read workload.

The subsequent patches fixes header seed mismatch issues.

Signed-off-by: Ankit Kumar <ankit.kumar@samsung.com>