vdpa: Sync calls set/get config/status with cf_mutex

vdpa: Sync calls set/get config/status with cf_mutex

[ Upstream commit 73bc0dbb591baea322a7319c735e5f6c7dba9cfb ]

Add wrappers to get/set status and protect these operations with
cf_mutex to serialize these operations with respect to get/set config
operations.

Signed-off-by: Eli Cohen <elic@nvidia.com>
Link: https://lore.kernel.org/r/20220105114646.577224-4-elic@nvidia.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Stable-dep-of: e40b6abe0b12 ("virtio_vdpa: fix misleading return in void function")
Signed-off-by: Sasha Levin <sashal@kernel.org>