The include was useful historically, its not anymore so lets remove it.
This should have no functional change except on any layers directly depending
on it or gcc-cross.inc but even then it would only impact sh4 and is easily
fixed if there was a problem.
(From OE-Core rev: e7e8fe11c34bf05179f3bbaa2fb1af7b7125696a)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>