SDL: Fixed n3ds build

SDL Commits
1 
From d95dbe78bb7a5087ecfb8d301417b1108d868738 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Mon, 12 Jun 2023 15:39:57 -0700
Subject: [PATCH] Fixed n3ds build

---
 src/joystick/SDL_joystick.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/joystick/SDL_joystick.c b/src/joystick/SDL_joystick.c
index f30eaa9a88d8..0a1e65b5fbab 100644
--- a/src/joystick/SDL_joystick.c
+++ b/src/joystick/SDL_joystick.c
@@ -139,9 +139,9 @@ SDL_bool SDL_JoysticksQuitting(void)
 
 void SDL_LockJoysticks(void)
 {
-    SDL_AtomicIncRef(&SDL_joystick_lock_pending);
+    (void)SDL_AtomicIncRef(&SDL_joystick_lock_pending);
     SDL_LockMutex(SDL_joystick_lock);
-    SDL_AtomicDecRef(&SDL_joystick_lock_pending);
+    (void)SDL_AtomicDecRef(&SDL_joystick_lock_pending);
 
     ++SDL_joysticks_locked;
 }