xen/pvcalls: remove set but not used variable 'intf'

xen/pvcalls: remove set but not used variable 'intf'

[ Upstream commit 1f8ce09b36c41a026a37a24b20efa32000892a64 ]

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/xen/pvcalls-back.c: In function 'pvcalls_sk_state_change':
drivers/xen/pvcalls-back.c:286:28: warning:
 variable 'intf' set but not used [-Wunused-but-set-variable]

It not used since e6587cdbd732 ("pvcalls-back: set -ENOTCONN in
pvcalls_conn_back_read")

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>