Revert "ping: always initialize ->sin6_scope_id and ->sin6_flowinfo"

This reverts commit 9b2a3cfa951ca2d99c68344ebbdeb9f600748770.
Revert "net: ipv6: Add IPv6 support to the ping socket."

This reverts commit 1bb64adfa5e31c5f0e36aa64911fa94f7b14a3d8.