microblaze: Simplify early console binding from DT

Recognize early Linux console from chosen - linux,stdout-path
instead of detecting the first console with appropriate
compatible strings.
This patch solved the problem on system with multiple
consoles.

Signed-off-by: Michal Simek <monstr@monstr.eu>
diff --git a/arch/microblaze/include/asm/prom.h b/arch/microblaze/include/asm/prom.h
index d0890d3..34c4e8b 100644
--- a/arch/microblaze/include/asm/prom.h
+++ b/arch/microblaze/include/asm/prom.h
@@ -26,8 +26,12 @@
 #define HAVE_ARCH_DEVTREE_FIXUPS
 
 /* Other Prototypes */
-extern int early_uartlite_console(void);
-extern int early_uart16550_console(void);
+enum early_consoles {
+	UARTLITE = 1,
+	UART16550 = 2,
+};
+
+extern int of_early_console(void *version);
 
 #ifdef CONFIG_PCI
 /*