uboot-phytec

ARM: da850-evm: Remove references to CONFIG_DA850_AM18X_EVM

With the removal of da850_am18xxevm, there is at least one
whitelisted CONFIG option that can be deleted.  This patch
removes CONFIG_DA850_AM18X_EVM since it's not required any more

Signed-off-by: Adam Ford <aford173@gmail.com>