Revert "tcp: enforce receive buffer memory limits by allowing the tcp window to shrink"

This reverts commit 0796c534 which is
commit b650d953 upstream.

It breaks the Android ABI so revert it for now, if it is needed in the
future, it can be brought back in an ABI-safe way.

Bug: 161946584
Change-Id: I6d4865da903caac56dbca2c7c0cfca14622760d4
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>