Revert "net: ipv6: fix wrong ping_v6_sendmsg return value"

This reverts commit 77a68063f332ddc7bbb519da7f82bad329baf6e6.
Revert "net: ipv6: add missing lock in ping_v6_sendmsg"

This reverts commit 00b8647e93f2d632e390ca34f2819631f059845c.
Revert "ping: always initialize ->sin6_scope_id and ->sin6_flowinfo"

This reverts commit e46ccd6bcef35f8227ecf3b3b6b9803bba188df3.
Revert "net: ipv6: Add IPv6 support to the ping socket."

This reverts commit deb89bfabad65a4d816258a56fe8f6c9a88d5bf7.