serial: samsung: disable DMA

It seems that dma implementation in serial/samsung.c has a malfunction.

Bug:33931804

Change-Id: I55cb9e4688d0f3773b36ae7a5d3c217ffe34f4b8
Signed-off-by: Shohei Sakamoto <sakamotos@casio.co.jp>
diff --git a/arch/arm/configs/koi_defconfig b/arch/arm/configs/koi_defconfig
index 95fe4bc..99e9d96 100644
--- a/arch/arm/configs/koi_defconfig
+++ b/arch/arm/configs/koi_defconfig
@@ -210,7 +210,6 @@
 # CONFIG_DEVMEM is not set
 # CONFIG_DEVKMEM is not set
 CONFIG_SERIAL_SAMSUNG=y
-CONFIG_SERIAL_SAMSUNG_DMA=y
 CONFIG_SERIAL_SAMSUNG_CONSOLE=y
 # CONFIG_HW_RANDOM is not set
 # CONFIG_I2C_EXYNOS5 is not set