ti: Convert CONFIG_TI_EDMA3 to Kconfig

This converts the following to Kconfig:
   CONFIG_TI_EDMA3

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>
diff --git a/configs/k2g_evm_defconfig b/configs/k2g_evm_defconfig
index dfd2f8b..aed3385 100644
--- a/configs/k2g_evm_defconfig
+++ b/configs/k2g_evm_defconfig
@@ -57,6 +57,7 @@
 CONFIG_DM=y
 CONFIG_SPL_DM=y
 CONFIG_DFU_MMC=y
+CONFIG_TI_EDMA3=y
 CONFIG_SYS_I2C_DAVINCI=y
 CONFIG_MISC=y
 CONFIG_SYS_I2C_EEPROM_ADDR=0x50