[ARM] 4476/1: EM7210/SS4000E support

This patch adds the basic support for the em7210 board. It is similar to
the iq31244 board and can be found on Intel "Baxter Creek" ss4000e nas.

Signed-off-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>