base.bbclass: drop obsolete HOSTTOOLS_WHITELIST_GPL-3.0
base.bbclass sets 'check_license' to False (and therefore skips
license checking completely) for native, nativesdk, etc recipes
(ie anything which could potentially be classed as "host tools"),
so supporting a dedicated whitelist of GPLv3 host tools is not
necessary.
Signed-off-by: Andre McCurdy <armccurdy@gmail.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
