xen: earlycpio: Pull in latest linux earlycpio.[ch]

xen: earlycpio: Pull in latest linux earlycpio.[ch]

AFAICT our current version does not correspond to any version in the
Linux history. This commit resynchronised to the state in Linux
commit 598bae70c2a8e35c8d39b610cca2b32afcf047af.

Differences from upstream: find_cpio_data is __init, printk instead of
pr_*.

This appears to fix Debian bug #785187. "Appears" because my test box
happens to be AMD and the issue is that the (valid) cpio generated by
the Intel ucode is not liked by the old Xen code. I've tested by
hacking the hypervisor to look for the Intel path.

Reported-by: Stephan Seitz <stse+debianbugs@fsing.rootsland.net>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Stephan Seitz <stse+debianbugs@fsing.rootsland.net>
Cc: 785187@bugs.debian.org
Acked-by: Jan Beulich <jbeulich@suse.com>