In order to deny device we need to check if there is any entry in BPF
map and we need to load the current value from map if there is already
entry for that device.  If both values are same we can remove that entry
but if they are different we need to update the entry because we don't
have to deny all access, but for example only write access.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>