um: remove pcap driver from documentation

We just removed the driver, but forgot the row in the
documentation table mentioning it. Remove that.

Link: https://patch.msgid.link/20240703172013.c3232dc5cbe9.I7f9941095d45a39d0f1e83680a408b3c6d445242@changeidAcked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Documentation/virt/uml/user_mode_linux_howto_v2.rst

@@ -223,8 +223,6 @@ remote UML and other VM instances.
 +-----------+--------+------------------------------------+------------+
 | socket    | legacy | none                               | ~ 450Mbit  |
 +-----------+--------+------------------------------------+------------+
-| pcap      | legacy | rx only                            | ~ 450Mbit  |
-+-----------+--------+------------------------------------+------------+
 | ethertap  | legacy | obsolete                           | ~ 500Mbit  |
 +-----------+--------+------------------------------------+------------+
 | vde       | legacy | obsolete                           | ~ 500Mbit  |