i.MX6: board: Add BTicino i.MX6DL Mamoj initial support

Add initial support for i.MX6DL BTicino Mamoj board.

Mamoh board added:
- SPL
- SPL_DM
- SPL_OF_CONTROL
- DM for U-Boot proper
- OF_CONTROL for U-Boot proper
- eMMC
- FEC
- Boot from eMMC
- Boot from USB SDP

Signed-off-by: Simone CIANNI <simone.cianni@bticino.it>
Signed-off-by: Raffaele RECALCATI <raffaele.recalcati@bticino.it>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>