sdl2-compat: Fix DetachVirtual prototype

SDL Commits
1 
From bfab757fe549775abfbec48dda6fbb22b820673b Mon Sep 17 00:00:00 2001
From: Sylvain <[EMAIL REDACTED]>
Date: Fri, 3 Feb 2023 21:10:04 +0100
Subject: [PATCH] Fix DetachVirtual prototype

---
 src/sdl2_compat.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/sdl2_compat.c b/src/sdl2_compat.c
index 0f76316..b1f3362 100644
--- a/src/sdl2_compat.c
+++ b/src/sdl2_compat.c
@@ -4251,10 +4251,10 @@ SDL_JoystickAttachVirtualEx(const SDL_VirtualJoystickDesc *desc)
 }
 
 DECLSPEC int SDLCALL
-SDL_JoystickDetachVirtual(SDL_JoystickID instance_id)
+SDL_JoystickDetachVirtual(int device_index)
 {
-    const SDL_JoystickID jid = GetJoystickInstanceFromIndex(instance_id);
-    return jid ? SDL3_DetachVirtualJoystick(jid) : SDL_FALSE;
+    const SDL_JoystickID jid = GetJoystickInstanceFromIndex(device_index);
+    return jid ? SDL3_DetachVirtualJoystick(jid) : -1;
 }