sdl12-compat: RWops12to20_size: remove the useless Sint64 cast on size

SDL Commits
1 
From 0d11cbf7a25861d07380cd14177d1b66abef9117 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Tue, 15 Jun 2021 11:55:02 +0300
Subject: [PATCH] RWops12to20_size: remove the useless Sint64 cast on size

Closes: https://github.com/libsdl-org/sdl12-compat/issues/109
---
 src/SDL12_compat.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/SDL12_compat.c b/src/SDL12_compat.c
index 17b536e..e17c1b5 100644
--- a/src/SDL12_compat.c
+++ b/src/SDL12_compat.c
@@ -5809,7 +5809,7 @@ RWops12to20_size(struct SDL_RWops *rwops20)
     if (pos == -1) {
         return SDL20_Error(SDL_EFSEEK);
     }
-    size = (Sint64) rwops12->seek(rwops12, 0, RW_SEEK_END);
+    size = rwops12->seek(rwops12, 0, RW_SEEK_END);
     rwops12->seek(rwops12, pos, RW_SEEK_SET);
     rwops20->hidden.unknown.data2 = (void *) ((size_t) size);
     return size;