Revert "ANDROID: GKI: Disable security lockdown for unsigned modules"

This reverts commit befc75e7.

It conflicts in bad ways with the module code changes in 5.19-rc1 so
revert it for now.  If it is still needed, it can be added back in
later.

Bug: 200082547
Bug: 214445388
Cc: Ramji Jiyani <ramjiyani@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ice884d241ae153a75facc1ca409ea5c59653cde3