[PATCH] ppc64: iSeries early printk breakage

The earlier commit 8d927391
(Consolidate early console and PPCDBG code) broke iSeries because
it caused unregister_console(&udbg_console) to be called
unconditionally.  iSeries never registers the udbg_console.

This just reverts part of the change.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/ppc64/kernel/udbg.c

@@ -158,14 +158,20 @@ static struct console udbg_console = {
 	.index	= -1,
 };
 
+static int early_console_initialized;
+
 void __init disable_early_printk(void)
 {
+	if (!early_console_initialized)
+		return;
 	unregister_console(&udbg_console);
+	early_console_initialized = 0;
 }
 
 /* called by setup_system */
 void register_early_udbg_console(void)
 {
+	early_console_initialized = 1;
 	register_console(&udbg_console);
 }