lguest: add iomem region, where guest page faults get sent to userspace.

This lets us implement PCI.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --cc drivers/lguest/lg.h
Simple merge

diff --cc drivers/lguest/lguest_user.c
Simple merge

diff --cc drivers/lguest/page_tables.c
Simple merge

diff --cc drivers/lguest/x86/core.c
Simple merge

diff --cc tools/lguest/lguest.c
Simple merge