i386: touch_nmi_watchdog() in print_trace_address()

Prevent NMI watchdog triggering during long sysrq-T outputs.

Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>