powerpc/powernv: Add PIO accessors for Power8 LPC bus

This uses the hooks provided by CONFIG_PPC_INDIRECT_PIO to
implement a set of hooks for IO port access to use the LPC
bus via OPAL calls for the first 64K of IO space

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powernv/setup.c

@@ -54,6 +54,12 @@ static void __init pnv_setup_arch(void)
 
 static void __init pnv_init_early(void)
 {
+	/*
+	 * Initialize the LPC bus now so that legacy serial
+	 * ports can be found on it
+	 */
+	opal_lpc_init();
+
 #ifdef CONFIG_HVC_OPAL
 	if (firmware_has_feature(FW_FEATURE_OPAL))
 		hvc_opal_init_early();