[PATCH] unwinder: always use unlocked module list access in unwinder fallback

We're already well protected against module unloads because module
unload uses stop_machine(). The only exception is NMIs, but other
users already risk lockless accesses here.

This avoids some hackery in lockdep and also a potential deadlock

This matches what i386 does.

Signed-off-by: Andi Kleen <ak@suse.de>