agp/intel: Fix missed cached memory flags setting in i965_write_entry()

This fixes regression from a6963596,
that missed to set cached memory type in GTT entry.
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/char/agp/intel-gtt.c

@@ -1192,12 +1192,19 @@ static void i9xx_chipset_flush(void)
 		writel(1, intel_private.i9xx_flush_page);
 }
 
-static void i965_write_entry(dma_addr_t addr, unsigned int entry,
+static void i965_write_entry(dma_addr_t addr,
+			     unsigned int entry,
 			     unsigned int flags)
 {
+	u32 pte_flags;
+
+	pte_flags = I810_PTE_VALID;
+	if (flags == AGP_USER_CACHED_MEMORY)
+		pte_flags |= I830_PTE_SYSTEM_CACHED;
+
 	/* Shift high bits down */
 	addr |= (addr >> 28) & 0xf0;
-	writel(addr | I810_PTE_VALID, intel_private.gtt + entry);
+	writel(addr | pte_flags, intel_private.gtt + entry);
 }
 
 static bool gen6_check_flags(unsigned int flags)