MIPS: Add 8250/16550 serial early printk driver

Signed-off-by: Yoichi Yuasa <yuasa@linux-mips.org>
Cc: linux-mips <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/947/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/Kconfig.debug b/arch/mips/Kconfig.debug
index 37871f0..b147e70 100644
--- a/arch/mips/Kconfig.debug
+++ b/arch/mips/Kconfig.debug
@@ -20,6 +20,14 @@
 	  doesn't cooperate with an X server. You should normally say N here,
 	  unless you want to debug such a crash.
 
+config EARLY_PRINTK_8250
+	bool "8250/16550 and compatible serial early printk driver"
+	depends on EARLY_PRINTK
+	default n
+	help
+	  If you say Y here, it will be possible to use a 8250/16550 serial
+	  port as the boot console.
+
 config CMDLINE_BOOL
 	bool "Built-in kernel command line"
 	default n