Fix for ARM64 /proc/kcore support.  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!".  At this point in
time, the kernel requires a patch to the ARM64 kern_addr_valid()
function to properly allow memory to be read from the kernel logical
memory map region.
(anderson@redhat.com)