lib/build_OID_registry: don't mention the full path of the script in output

This change strips the full path of the script generating
lib/oid_registry_data.c to just lib/build_OID_registry.  The motivation
for this change is Yocto emitting a build warning

	File /usr/src/debug/linux-lxatac/6.7-r0/lib/oid_registry_data.c in package linux-lxatac-src contains reference to TMPDIR [buildpaths]

So this change brings us one step closer to make the build result
reproducible independent of the build path.

Link: https://lkml.kernel.org/r/20240313211957.884561-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>