linux-tools: don't build perf when GPLv3 in INCOMPATIBLE_LICENSE
As binutils is required by perf to build and is GPLv3 licensed adding
GPLv3 to INCOMPATIBLE_LICENSE will cause linux-yocto to be skipped.
Long term we should look at moving perf to a separate recipe but as a
short term solution this patch will ensure that when GPLv3 is in
INCOMPATIBLE_LICENSE perf is not built and it's dependencies are not
added to build.
