pit: update I2C4 speed constant

BUG=none
BRANCH=none
TEST=tested on pit

Change-Id: I61896f70f41eec12a1499307f695fa69f3d42d88
Reviewed-on: https://gerrit.chromium.org/gerrit/59692
Reviewed-by: Gabe Black <gabeblack@chromium.org>
Commit-Queue: David Hendricks <dhendrix@chromium.org>
Tested-by: David Hendricks <dhendrix@chromium.org>
diff --git a/src/mainboard/google/pit/exynos5420.h b/src/mainboard/google/pit/exynos5420.h
index 562d9bc..21b704c 100644
--- a/src/mainboard/google/pit/exynos5420.h
+++ b/src/mainboard/google/pit/exynos5420.h
@@ -19,7 +19,7 @@
 
 /* I2C */
 #define I2C_0_SPEED 100000
-#define I2C_4_SPEED 100000
+#define I2C_4_SPEED 1000000	/* 1MHz */
 #define I2C_SLAVE 0
 
 /* Voltages */