boards: ls2088a: Add support of I2C driver model.

DM_I2C_COMPAT is a compatibility layer that allows using the non-DM
I2C API when DM_I2C is used.When DM_I2C_COMPAT is not enabled for
compilation, a compilation error will be generated. This patch
solves the problem that the i2c-related api of the ls2088a platform
does not support dm.

Signed-off-by: Chuanhua Han <chuanhua.han@nxp.com>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
diff --git a/include/configs/ls2080a_common.h b/include/configs/ls2080a_common.h
index c7d8a3b..6be581a 100644
--- a/include/configs/ls2080a_common.h
+++ b/include/configs/ls2080a_common.h
@@ -75,7 +75,9 @@
 #define CONFIG_SYS_MALLOC_LEN		(CONFIG_ENV_SIZE + 2048 * 1024)
 
 /* I2C */
+#ifndef CONFIG_DM_I2C
 #define CONFIG_SYS_I2C
+#endif
 
 /* Serial Port */
 #define CONFIG_SYS_NS16550_SERIAL