KVM: MMU: Fix another largepage memory leak

KVM: MMU: Fix another largepage memory leak

upstream commit: c5bc22424021cabda862727fb3f5098b866f074d

In the paging_fetch function rmap_remove is called after setting a large
pte to non-present. This causes rmap_remove to not drop the reference to
the large page. The result is a memory leak of that page.

Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
[chrisw: backport to 2.6.29]
Signed-off-by: Chris Wright <chrisw@sous-sol.org>