kernel: Build a perf package for 4.11/4.9 kernels

Extract the perf binary from the kernel package and create
a new perf package for each kernel. The perf package uses the
same tags as the kernel package and only contains the perf
binary under /usr/bin. The perf package can be added to the
init section or included as a stage in a multi-stage build
for other packages.

Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>

kernel/Dockerfile.perf

@@ -0,0 +1,10 @@
+# This Dockerfile extracts the perf utility from a kernel package and
+# places it into a scratch image
+ARG IMAGE
+FROM ${IMAGE} AS kernel
+
+FROM scratch
+ENTRYPOINT []
+CMD []
+WORKDIR /
+COPY --from=kernel /perf /usr/bin/perf