Revert "net: netlink: add NLM_F_BULK delete request modifier"

This reverts commit 6dea96a8 which is
commit 545528d7 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: I8481c837c6822c562f748152030b18b2bf780dfe
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>