Convert CONFIG_SYS_I2C_DAVINCI to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_I2C_DAVINCI

Signed-off-by: Adam Ford <aford173@gmail.com>
diff --git a/configs/legoev3_defconfig b/configs/legoev3_defconfig
index 7296603..7b8f169 100644
--- a/configs/legoev3_defconfig
+++ b/configs/legoev3_defconfig
@@ -23,6 +23,7 @@
 CONFIG_CMD_EXT4=y
 CONFIG_CMD_FAT=y
 CONFIG_CMD_DIAG=y
+CONFIG_SYS_I2C_DAVINCI=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_STMICRO=y
 CONFIG_SYS_NS16550=y