snow: use bootblock build class for UART code

This gets rid of a bunch of copy + pasted code from Exynos UART
files.

Change-Id: I9fbb6d79a40a338c9fdecd495544ff207909fd37
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/2286
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins)

src/cpu/samsung/exynos5250/Makefile.inc

@@ -8,6 +8,8 @@
 # in the bootblock and try moving it entirely into romstage.
 bootblock-y += clock_init.c
 bootblock-y += clock.c
+bootblock-y += soc.c
+bootblock-y += uart.c
 
 romstage-y += clock.c
 romstage-y += clock_init.c

src/cpu/samsung/exynos5250/uart.c

@@ -188,7 +188,7 @@ static void exynos5_uart_tx_byte(unsigned char data)
 	writeb(data, &uart->utxh);
 }
 
-#ifndef __PRE_RAM__
+#if !defined(__PRE_RAM__) && !defined(__BOOT_BLOCK__)
 static const struct console_driver exynos5_uart_console __console = {
 	.init     = exynos5_init_dev,
 	.tx_byte  = exynos5_uart_tx_byte,