Fix for KVM dumpfiles created with "virsh dump --memory-only" if
an X86_64 kernel was loaded with a non-zero "phys_base".  Without
the patch, the crash session fails with the warning message "WARNING:
cannot read linux_banner string" followed by the fatal error message
"crash: vmlinux and <dumpfile name> do not match!".
(anderson@redhat.com)