MAINTAINERS: Add a maintainer for bpftool

I've been contributing and reviewing patches for bpftool for some time,
and I'm taking care of its external mirror. On Alexei, KP, and Daniel's
suggestion, I would like to step forwards and become a maintainer for
the tool. This patch adds a dedicated entry to MAINTAINERS.
Signed-off-by: NQuentin Monnet <quentin@isovalent.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJakub Kicinski <kuba@kernel.org>
Acked-by: NKP Singh <kpsingh@kernel.org>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220608121428.69708-1-quentin@isovalent.com

MAINTAINERS

@@ -3731,6 +3731,13 @@ F:	include/linux/bpf_lsm.h
 F:	kernel/bpf/bpf_lsm.c
 F:	security/bpf/
 
+BPFTOOL
+M:	Quentin Monnet <quentin@isovalent.com>
+L:	bpf@vger.kernel.org
+S:	Maintained
+F:	kernel/bpf/disasm.*
+F:	tools/bpf/bpftool/
+
 BROADCOM B44 10/100 ETHERNET DRIVER
 M:	Michael Chan <michael.chan@broadcom.com>
 L:	netdev@vger.kernel.org