There is no reason to set an empty default for it, while not doing it
for all other potential WHITELIST_* variables. The reason it was set
here is a leftover from before when it was actually set to a value.
(From OE-Core rev: 22ccd479147744fcbf4f2e765e54da8d3d3d9c7f)
Signed-off-by: Peter Kjellerstedt <peter.kjellerstedt@axis.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>