(svn r1856) Make GfxInitSpriteMem() static, because it's only used withing spritecache.c

spritecache.c

@@ -951,7 +951,7 @@ static void LoadSpriteTables(void)
 	_compact_cache_counter = 0;
 }
 
-void GfxInitSpriteMem(byte *ptr, uint32 size)
+static void GfxInitSpriteMem(byte *ptr, uint32 size)
 {
 	// initialize sprite cache heap
 	_spritecache_ptr = ptr;

spritecache.h

@@ -20,7 +20,6 @@ const SpriteDimension *GetSpriteDimension(SpriteID sprite);
 Sprite *GetSprite(SpriteID sprite);
 byte *GetNonSprite(SpriteID sprite);
 
-void GfxInitSpriteMem(byte *ptr, uint32 size);
 void GfxLoadSprites(void);
 void IncreaseSpriteLRU(void);