Revert "scsi: sd: Keep disk read-only when re-reading partition"

This reverts commit 20bd1d02.

This patch introduced regressions for devices that come online in
read-only state and subsequently switch to read-write.

Given how the partition code is currently implemented it is not
possible to persist the read-only flag across a device revalidate
call. This may need to get addressed in the future since it is common
for user applications to proactively call BLKRRPART.

Reverting this commit will re-introduce a regression where a
device-initiated revalidate event will cause the admin state to be
forgotten. A separate patch will address this issue.

Fixes: 20bd1d02 ("scsi: sd: Keep disk read-only when re-reading partition")
Cc: <stable@vger.kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>