kbuild: deb-pkg: don't set KBUILD_BUILD_VERSION unconditionally

[ Upstream commit 6260406 ]

In ThinPro, we use the convention <upstream_ver>+hp<patchlevel> for
the kernel package. This does not have a dash in the name or version.
This is built by editing ".version" before a build, and setting
EXTRAVERSION="+hp" and KDEB_PKGVERSION make variables:

    echo 68 > .version
    make -j<n> EXTRAVERSION="+hp" bindeb-pkg KDEB_PKGVERSION=6.12.2+hp69

    .deb name: linux-image-6.12.2+hp_6.12.2+hp69_amd64.deb

Since commit 7d4f07d ("kbuild: deb-pkg: squash
scripts/package/deb-build-option to debian/rules"), this no longer
works. The deb build logic changed, even though, the commit message
implies that the logic should be unmodified.

Before, KBUILD_BUILD_VERSION was not set if the KDEB_PKGVERSION did
not contain a dash. After the change KBUILD_BUILD_VERSION is always
set to KDEB_PKGVERSION. Since this determines UTS_VERSION, the uname
output to look off:

    (now)      uname -a: version 6.12.2+hp ... #6.12.2+hp69
    (expected) uname -a: version 6.12.2+hp ... #69

Update the debian/rules logic to restore the original behavior.

Fixes: 7d4f07d ("kbuild: deb-pkg: squash scripts/package/deb-build-option to debian/rules")
Signed-off-by: Alexandru Gagniuc <alexandru.gagniuc@hp.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Alexandru Gagniuc

scripts/package/debian/rules

@@ -21,9 +21,11 @@ ifeq ($(origin KBUILD_VERBOSE),undefined)
     endif
 endif
 
-revision = $(lastword $(subst -, ,$(shell dpkg-parsechangelog -S Version)))
+revision = $(shell dpkg-parsechangelog -S Version | sed -n 's/.*-//p')
 CROSS_COMPILE ?= $(filter-out $(DEB_BUILD_GNU_TYPE)-, $(DEB_HOST_GNU_TYPE)-)
-make-opts = ARCH=$(ARCH) KERNELRELEASE=$(KERNELRELEASE) KBUILD_BUILD_VERSION=$(revision) $(addprefix CROSS_COMPILE=,$(CROSS_COMPILE))
+make-opts = ARCH=$(ARCH) KERNELRELEASE=$(KERNELRELEASE) \
+    $(addprefix KBUILD_BUILD_VERSION=,$(revision)) \
+    $(addprefix CROSS_COMPILE=,$(CROSS_COMPILE))
 
 binary-targets := $(addprefix binary-, image image-dbg headers libc-dev)