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>

Author: Uwe Kleine-König

lib/build_OID_registry

@@ -8,6 +8,7 @@
 #
 
 use strict;
+use Cwd qw(abs_path);
 
 my @names = ();
 my @oids = ();
@@ -17,6 +18,8 @@ if ($#ARGV != 1) {
     exit(2);
 }
 
+my $abs_srctree = abs_path($ENV{'srctree'});
+
 #
 # Open the file to read from
 #
@@ -35,7 +38,7 @@ close IN_FILE || die;
 #
 open C_FILE, ">$ARGV[1]" or die;
 print C_FILE "/*\n";
-print C_FILE " * Automatically generated by ", $0, ".  Do not edit\n";
+print C_FILE " * Automatically generated by ", $0 =~ s#^\Q$abs_srctree/\E##r, ".  Do not edit\n";
 print C_FILE " */\n";
 
 #