Instead of cross using cross-directory makefile directives,
add a Makefile in board/cssi/common/ directory in order to
benefit from HAVE_VENDOR_COMMON_LIB logic.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

In preparation of the new cssi board called cmpcpro which
we be introduce in a future patch, move common
functions into a dedicated file in a common directory.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

This adds a new board from CS GROUP. The board is called
MCR3000_2G, and has a CPU board called CMPC885.

That CPU board is shared with another equipment that will
be added in a later patch.

That board stores Ethernet MAC addresses in an EEPROM which
is accessed using SPI bus.

This patch was originally written by Charles Frey who's
email address is not valid anymore as he left the company.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: FRANJOU Stephane <stephane.franjou@csgroup.eu>