sanity: skip make 4.2.1 warning for debian

sanity: skip make 4.2.1 warning for debian

This is a follow up patch of:
ad5829aa1f8a (sanity: Show a warning that make 4.2.1 is buggy on non-ubuntu systems)

Debian10 has the exact same version/sources for make as Ubuntu
(focal), e.g. https://packages.debian.org/source/buster/make-dfsg and
https://packages.ubuntu.com/source/focal/make-dfsg.

As per the corresponding changelog, the patch mentioned in
ad5829aa1f8a, is included in both Debian and Ubuntu in make
4.2.1-1.1. So it's safe to use make 4.2.1 in Debian10.

Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>