[Build] disable DOCKER_BUILDKIT if SONIC_USE_DOCKER_BUILDKIT is not set

[k-v1]

Why I did it

Fix #14081
By default DOCKER_BUILDKIT is enabled after docker version 23.0.0
So we need to disable it explicitly if SONIC_USE_DOCKER_BUILDKIT is not set.
Otherwise it will produce larger installable images.

How I did it

set DOCKER_BUILDKIT=0 in slave.mk

How to verify it

[k-v1]

It makes sense when SONIC_CONFIG_USE_NATIVE_DOCKERD_FOR_BUILD is enabled and build system is Ubuntu 22.04 or something like this with new docker version.

[k-v1]

@lguohan Could you please review this PR?

At this moment we don't use DOCKER_BUILDKIT by default because there is the old docker bug leads to larger SONiC images:

sonic-buildimage/rules/config

Lines 23 to 29 in e32624d

	# SONIC_USE_DOCKER_BUILDKIT - use docker buildkit for build.
	# If set to y SONiC build system will set environment variable DOCKER_BUILDKIT=1
	# to enable docker buildkit.
	# This options will speed up docker image build time.
	# NOTE: SONIC_USE_DOCKER_BUILDKIT will produce larger installable SONiC image
	# because of a docker bug (more details: https://github.com/moby/moby/issues/38903)
	# SONIC_USE_DOCKER_BUILDKIT = y

In February docker 23 was released and DOCKER_BUILDKIT is enabled by default now in new docker versions.
At this moment it affects only builds when SONIC_CONFIG_USE_NATIVE_DOCKERD_FOR_BUILD is enabled and new docker version is installed on the build system.
In my case it was a PC with Ubuntu 22.04 and docker 23.0.1. Also I use SONIC_CONFIG_USE_NATIVE_DOCKERD_FOR_BUILD to build SONiC images. I faced this bug and it took some time to find the cause.
So I recommend to merge this fix. It doesn't affect current builds, but fix this bug when we build SONiC with new docker versions.

[lguohan]

thanks for explanation, approved, and will merge once test passed.

[xumia]

/azp run Azure.sonic-buildimage

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