Revert "net: inline sock_prot_inuse_add()"

This reverts commit aa4ed1e0 which is
commit 2a12ae5d upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I2450317e43e50367d34a07c37e3628ebf4f48276
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>