omap2+: Fix omap_serial_early_init to work with init_early hook

The new init_early hook happens at the end of setup_arch,
which is too early for kzalloc. However, there's no need
to call omap_serial_early_init that early, so fix this
by setting it up as a core_initcall.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Tested-by: Kevin Hilman <khilman@ti.com>

arch/arm/mach-omap2/io.c

@@ -398,8 +398,6 @@ void __init omap2_init_common_infrastructure(void)
 void __init omap2_init_common_devices(struct omap_sdrc_params *sdrc_cs0,
 				      struct omap_sdrc_params *sdrc_cs1)
 {
-	omap_serial_early_init();
-
 	if (cpu_is_omap24xx() || cpu_is_omap34xx()) {
 		omap2_sdrc_init(sdrc_cs0, sdrc_cs1);
 		_omap2_init_reprogram_sdrc();

arch/arm/mach-omap2/serial.c

@@ -655,7 +655,7 @@ static void serial_out_override(struct uart_port *up, int offset, int value)
 }
 #endif
 
-void __init omap_serial_early_init(void)
+static int __init omap_serial_early_init(void)
 {
 	int i = 0;
 
@@ -672,7 +672,7 @@ void __init omap_serial_early_init(void)
 
 		uart = kzalloc(sizeof(struct omap_uart_state), GFP_KERNEL);
 		if (WARN_ON(!uart))
-			return;
+			return -ENODEV;
 
 		uart->oh = oh;
 		uart->num = i++;
@@ -691,7 +691,10 @@ void __init omap_serial_early_init(void)
 		 */
 		uart->oh->flags |= HWMOD_INIT_NO_IDLE | HWMOD_INIT_NO_RESET;
 	} while (1);
+
+	return 0;
 }
+core_initcall(omap_serial_early_init);
 
 /**
  * omap_serial_init_port() - initialize single serial port

arch/arm/plat-omap/include/plat/serial.h

@@ -96,7 +96,6 @@
 
 struct omap_board_data;
 
-extern void __init omap_serial_early_init(void);
 extern void omap_serial_init(void);
 extern void omap_serial_init_port(struct omap_board_data *bdata);
 extern int omap_uart_can_sleep(void);