bpftool: Remove inclusion of utilities.mak from Makefiles

bpftool: Remove inclusion of utilities.mak from Makefiles

BugLink: https://bugs.launchpad.net/bugs/1959376
commit 48f5aef4c458c19ab337eed8c95a6486cc014aa3 upstream.

Bpftool's Makefile, and the Makefile for its documentation, both include
scripts/utilities.mak, but they use none of the items defined in this
file. Remove the includes.

Fixes: 71bb428fe2c1 ("tools: bpf: add bpftool")
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211110114632.24537-3-quentin@isovalent.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>