Return value of function get_device() is not checking before
dereference. Fix this problem by adding checking condition.
Coverity issue: 119262
Fixes: 77d20126b4c2 ("vhost-user: handle message to enable vring")
Signed-off-by: Marcin Kerlin <marcinx.kerlin@intel.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
b497724652