Revert "binder: fix max_thread type inconsistency"

This reverts commit ddbcd7d36e3899cdb255fbbeef40127f6ef39d98 which is
commit 42316941335644a98335f209daafa4c122f28983 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: If5c3cf2234d5e3cfb2a59de792d89bc0eea15885
Cc: Carlos Llamas <cmllamas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/android/binder.c

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 0a8c21c..2d0fae7 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -5519,7 +5519,7 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 			goto err;
 		break;
 	case BINDER_SET_MAX_THREADS: {
-		u32 max_threads;
+		int max_threads;
 
 		if (copy_from_user(&max_threads, ubuf,
 				   sizeof(max_threads))) {

drivers/android/binder_internal.h

diff --git a/drivers/android/binder_internal.h b/drivers/android/binder_internal.h
index c697be7..696353b 100644
--- a/drivers/android/binder_internal.h
+++ b/drivers/android/binder_internal.h
@@ -447,7 +447,7 @@ struct binder_proc {
 	struct list_head todo;
 	struct binder_stats stats;
 	struct list_head delivered_death;
-	u32 max_threads;
+	int max_threads;
 	int requested_threads;
 	int requested_threads_started;
 	int tmp_ref;