serial: bfin_5xx: fix building as module when early printk is enabled

Since early printk only makes sense/works when the serial driver is built
into the kernel, disable the option for this driver when it is going to be
built as a module.  Otherwise we get build failures due to the ifdef
handling.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: stable <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/serial/bfin_5xx.c

@@ -42,6 +42,10 @@
 # undef CONFIG_EARLY_PRINTK
 #endif
 
+#ifdef CONFIG_SERIAL_BFIN_MODULE
+# undef CONFIG_EARLY_PRINTK
+#endif
+
 /* UART name and device definitions */
 #define BFIN_SERIAL_NAME	"ttyBF"
 #define BFIN_SERIAL_MAJOR	204