powerpc/4xx: PCIe driver now detects if a port is disabled via the dev-tree

This patch add a check to the PPC4xx PCIe driver to detect if the port
is disabled via the device-tree. This is needed for the AMCC Canyonlands
board which has an option to either select 2 PCIe ports or 1 PCIe port
and one SATA port. The SATA port and the 1st PCIe port pins are multiplexed
so we can't start both drivers.

Signed-off-by: Stefan Roese <[e-mail]>
Acked-by: Benjamin Herrenschmidt <[e-mail]>
Signed-off-by: Josh Boyer <[e-mail]>

arch/powerpc/sysdev/ppc4xx_pci.c

···
 	}
 	port = &ppc4xx_pciex_ports[portno];
 	port->index = portno;
+
+	/*
+	 * Check if device is enabled
+	 */
+	if (!of_device_is_available(np)) {
+		printk(KERN_INFO "PCIE%d: Port disabled via device-tree\n", port->index);
+		return;
+	}
+
 	port->node = of_node_get(np);
 	pval = of_get_property(np, "sdr-base", NULL);
 	if (pval == NULL) {