x86: Fix objdump version check in chkobjdump.awk for different formats.

Different version of objdump says its version in different way;

GNU objdump 2.16.1

or

GNU objdump version 2.19.51.0.14-1.fc11 20090722

This patch uses the first argument which starts with a number
as version string.

Changes in v2:
 - Remove unneeded increment.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <20091218154012.16960.5113.stgit@dhcp-100-2-132.bos.redhat.com>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>