boards: microchip: mec_assy6941: Add support for MEC1653B

We added support for the MEC1653B daughter card on the
mec_assy6941 EVB base board. We removed variant specific
kconfig files since none of the boards require board
specific settings.

Signed-off-by: Scott Worley <scott.worley@microchip.com>
9 files changed