arm64: Fix duplicate definition of early_console

When compiling with allmodconfig. early_console is already defined as an
extern global pointer. Need let it point to the object which we intend
to (like arm32 done).
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/kernel/early_printk.c

@@ -95,7 +95,7 @@ static void early_write(struct console *con, const char *s, unsigned n)
 	}
 }
 
-static struct console early_console = {
+static struct console early_console_dev = {
 	.name =		"earlycon",
 	.write =	early_write,
 	.flags =	CON_PRINTBUFFER | CON_BOOT,
@@ -145,7 +145,8 @@ static int __init setup_early_printk(char *buf)
 		early_base = early_io_map(paddr, EARLYCON_IOBASE);
 
 	printch = match->printch;
-	register_console(&early_console);
+	early_console = &early_console_dev;
+	register_console(&early_console_dev);
 
 	return 0;
 }