binder: fix pointer cast warning

binder_uintptr_t is not the same as uintptr_t, so converting it into a
pointer requires a second cast:

drivers/android/binder.c: In function 'binder_translate_fd_array':
drivers/android/binder.c:2511:28: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
 2511 |         sender_ufda_base = (void __user *)sender_uparent->buffer + fda->parent_offset;
      |                            ^

Fixes: 656e01f ("binder: read pre-translated fds from sender buffer")
Acked-by: Todd Kjos <tkjos@google.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20211207122448.1185769-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/android/binder.c

@@ -2508,7 +2508,8 @@ static int binder_translate_fd_array(struct list_head *pf_head,
 	 */
 	fda_offset = (parent->buffer - (uintptr_t)t->buffer->user_data) +
 		fda->parent_offset;
-	sender_ufda_base = (void __user *)sender_uparent->buffer + fda->parent_offset;
+	sender_ufda_base = (void __user *)(uintptr_t)sender_uparent->buffer +
+				fda->parent_offset;
 
 	if (!IS_ALIGNED((unsigned long)fda_offset, sizeof(u32)) ||
 	    !IS_ALIGNED((unsigned long)sender_ufda_base, sizeof(u32))) {