xaa: convert pScrn->pScreen to use accessor.

This uses a standard conversion function to do the conversion.
Reviewed-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

hw/xfree86/xaa/xaaInit.c

@@ -92,7 +92,7 @@ XAADestroyInfoRec(XAAInfoRecPtr infoRec)
         return;
 
     if (infoRec->ClosePixmapCache)
-        (*infoRec->ClosePixmapCache) (infoRec->pScrn->pScreen);
+        (*infoRec->ClosePixmapCache) (xf86ScrnToScreen(infoRec->pScrn));
 
     free(infoRec->PreAllocMem);
 

hw/xfree86/xaa/xaaPCache.c

@@ -2015,7 +2015,7 @@ XAAWriteBitmapToCacheLinear(ScrnInfoPtr pScrn,
                             int x, int y, int w, int h,
                             unsigned char *src, int srcwidth, int fg, int bg)
 {
-    ScreenPtr pScreen = pScrn->pScreen;
+    ScreenPtr pScreen = xf86ScrnToScreen(pScrn);
     PixmapPtr pScreenPix, pDstPix;
     ChangeGCVal gcvals[2];
     GCPtr pGC;
@@ -2061,7 +2061,7 @@ XAAWritePixmapToCacheLinear(ScrnInfoPtr pScrn,
                             unsigned char *src,
                             int srcwidth, int bpp, int depth)
 {
-    ScreenPtr pScreen = pScrn->pScreen;
+    ScreenPtr pScreen = xf86ScrnToScreen(pScrn);
     PixmapPtr pScreenPix, pDstPix;
     GCPtr pGC;