datarmnet: Remove monaco_go and monaco_go_aon from BOARD_PLATFORM_LIST

For wearable line of devices derived from monaco, monaco will be used as
TARGET_BOARD_PLATFORM. Change removes others variants which were added
to support _go and _go_aon variants.

Change-Id: Id3ef3aa94ad0c80701260417d92eecf1b96558dd
Signed-off-by: Kaustubh Pandey <quic_kapandey@quicinc.com>