Convert CONFIG_SYS_I2C_OMAP24XX to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_I2C_OMAP24XX

Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
diff --git a/configs/ti816x_evm_defconfig b/configs/ti816x_evm_defconfig
index 0f9b905..9d4be2a 100644
--- a/configs/ti816x_evm_defconfig
+++ b/configs/ti816x_evm_defconfig
@@ -39,6 +39,7 @@
 CONFIG_DM=y
 CONFIG_DM_GPIO=y
 CONFIG_DM_I2C=y
+CONFIG_SYS_I2C_OMAP24XX=y
 CONFIG_MMC_OMAP_HS=y
 CONFIG_SYS_NS16550=y
 # CONFIG_USE_PRIVATE_LIBGCC is not set