Make KVMSlot a real structure

Make KVMSlot a real structure

struct kvm_userspace_memory_region does not use QEMU friendly types to
define memory slots.  This results in lots of ugly casting with warnings
on 32-bit platforms.

This patch introduces a proper KVMSlot structure that uses QEMU types to
describe memory slots.  This eliminates many of the casts and isolates
the type conversions to one spot.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5755 c046a42c-6fe2-441c-8c8c-71466251a162