msf2: Add EMAC block to SmartFusion2 SoC

With SmartFusion2 Ethernet MAC model in
place this patch adds the same to SoC.

Signed-off-by: Subbaraya Sundeep <sundeep.lkml@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 1587048891-30493-3-git-send-email-sundeep.lkml@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>