net: caif: fix memory leak in cfusbl_device_notify

In case of caif_enroll_dev() fail, allocated
link_support won't be assigned to the corresponding
structure. So simply free allocated pointer in case
of error.

Fixes: 7ad65bf6 ("caif: Add support for CAIF over CDC NCM USB interface")
Cc: stable@vger.kernel.org
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>