Revert "binder: fix max_thread type inconsistency"

This reverts commit 71df2cb2 which is
commit 42316941 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: I1a16bec24ff2856abdab6f52ab5363173d87aa91
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>