binder: fix comment on binder_alloc_new_buf() return value

Update the comments of binder_alloc_new_buf() to reflect that the return
value of the function is now ERR_PTR(-errno) on failure.

No functional changes in this patch.

Cc: stable@vger.kernel.org
Fixes: 57ada2fb ("binder: add log information for binder transaction failures")
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20231201172212.1813387-8-cmllamas@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/android/binder_alloc.c

@@ -556,7 +556,7 @@ static struct binder_buffer *binder_alloc_new_buf_locked(
  * is the sum of the three given sizes (each rounded up to
  * pointer-sized boundary)
  *
- * Return:	The allocated buffer or %NULL if error
+ * Return:	The allocated buffer or %ERR_PTR(-errno) if error
  */
 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 					   size_t data_size,