[dwarfdump] Lookup needs to be an unsigned long long parameter.

Before this patch, dwarfdump's lookup parameter only accepts unsigned.
Given that for many current platforms the load address already exceeds
unsigned (e.g. arm64 w/ 0x100000000), dwarfdump needs an unsigned long
long parameter.

Patch by: Dr. Michael 'Mickey' Lauer <mickey@vanille-media.de>

llvm-svn: 321064