intelfb: fixup p calculation

This fixes up the p calculation of p1 and p2 for the i9xx chipsets.
This seems to work a lot better for lower pixel clocks..

Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/video/intelfb/intelfbdrv.c b/drivers/video/intelfb/intelfbdrv.c
index 54ce745..9e83664 100644
--- a/drivers/video/intelfb/intelfbdrv.c
+++ b/drivers/video/intelfb/intelfbdrv.c
@@ -1480,7 +1480,7 @@
 	intelfbhw_cursor_hide(dinfo);
 
 	/* If XFree killed the cursor - restore it */
-	physical = (dinfo->mobile || IS_I9xx(dinfo)) ? dinfo->cursor.physical :
+	physical = (dinfo->mobile || IS_I9XX(dinfo)) ? dinfo->cursor.physical :
 		   (dinfo->cursor.offset << 12);
 
 	if (INREG(CURSOR_A_BASEADDR) != physical) {