The kernel-doc script triggers a perl warning when invoked
without KERNELVERSION in the environment, rather make it use
the string "unknown kernel version" instead.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>