qa: agetty entry in selinux allowlist is redundant now

With teuthology.git commit 2edcefaa5da1 ("teuthology/task/selinux:
ignore denials in agetty"), it's ignored globally.  This effectively
reverts commit 7a63892 ("qa: ignore container checkpoint/restore
related selinux denials for centos9").

Signed-off-by: Ilya Dryomov <[email protected]>

Author: idryomov

qa/distros/all/centos_9.stream.yaml

@@ -1,6 +1,2 @@
 os_type: centos
 os_version: "9.stream"
-overrides:
-  selinux:
-    allowlist:
-      - scontext=system_u:system_r:getty_t:s0

qa/distros/podman/centos_9.stream.yaml

@@ -4,4 +4,3 @@ overrides:
   selinux:
     allowlist:
       - scontext=system_u:system_r:logrotate_t:s0
-      - scontext=system_u:system_r:getty_t:s0