[ Upstream commit 94a980c39c8e3f8abaff5d3b5bbcd4ccf1c02c4f ]

Fix a call to userspace_mem_region_find to conform to its spec of
taking an inclusive, inclusive range. It was previously being called
with an inclusive, exclusive range. Also remove a redundant region bounds
check in vm_userspace_mem_region_add. Region overlap checking is already
performed by the call to userspace_mem_region_find.

Tested: Compiled tools/testing/selftests/kvm with -static
	Ran all resulting test binaries on an Intel Haswell test machine
	All tests passed
Signed-off-by: NBen Gardon <bgardon@google.com>
Reviewed-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>