radeonfb: Add support for Radeon xpress 200m

Added support for radeon xpress 200m(rs480).  Note that the card doesn't
like dynclk turned on.

Signed-off-by: Johan Henriksson <jhn98032@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/aty/radeon_pm.c

@@ -2826,11 +2826,15 @@ void radeonfb_pm_init(struct radeonfb_info *rinfo, int dynclk, int ignore_devlis
 	rinfo->pm_reg = pci_find_capability(rinfo->pdev, PCI_CAP_ID_PM);
 
 	/* Enable/Disable dynamic clocks: TODO add sysfs access */
-	rinfo->dynclk = dynclk;
-	if (dynclk == 1) {
+	if (rinfo->family == CHIP_FAMILY_RS480)
+		rinfo->dynclk = -1;
+	else
+		rinfo->dynclk = dynclk;
+
+	if (rinfo->dynclk == 1) {
 		radeon_pm_enable_dynamic_mode(rinfo);
 		printk("radeonfb: Dynamic Clock Power Management enabled\n");
-	} else if (dynclk == 0) {
+	} else if (rinfo->dynclk == 0) {
 		radeon_pm_disable_dynamic_mode(rinfo);
 		printk("radeonfb: Dynamic Clock Power Management disabled\n");
 	}