arm:exynos: add common DTS file for exynos 4

This patch adds common dtsi file and config header for all
Exynos 4 based boards.

Patch additionaly adds board specific (weak) functions for
board_early_init_f and board_power_init functions.

Signed-off-by: Piotr Wilczek <p.wilczek@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
diff --git a/board/samsung/common/board.c b/board/samsung/common/board.c
index f8562b2..cf78d36 100644
--- a/board/samsung/common/board.c
+++ b/board/samsung/common/board.c
@@ -33,6 +33,20 @@
 
 static struct local_info local;
 
+int __exynos_early_init_f(void)
+{
+	return 0;
+}
+int exynos_early_init_f(void)
+	__attribute__((weak, alias("__exynos_early_init_f")));
+
+int __exynos_power_init(void)
+{
+	return 0;
+}
+int exynos_power_init(void)
+	__attribute__((weak, alias("__exynos_power_init")));
+
 #if defined CONFIG_EXYNOS_TMU
 /* Boot Time Thermal Analysis for SoC temperature threshold breach */
 static void boot_temp_check(void)
@@ -140,7 +154,7 @@
 	board_i2c_init(gd->fdt_blob);
 #endif
 
-	return err;
+	return exynos_early_init_f();
 }
 #endif
 
@@ -284,7 +298,7 @@
 	ret = max77686_init();
 #endif
 
-	return ret;
+	return exynos_power_init();
 }
 #endif