arm: mvebu: clearfog: Add option for 2.5 Gbps SFP

While newer Linux kernels provide autoconfiguration of SFP, provide
an option for setting in U-Boot Kconfig for use prior to booting.

Signed-off-by: Joel Johnson <mrjoel@lixil.net>
Reviewed-by: Stefan Roese <sr@denx.de>
2 files changed