msm: emac: support SGMII link with auto-neg off

Add the feature to support the SGMI-to-SGMII link with
auto-negotiation turned off.

Change-Id: I7f1759b9079eae7be68fff7e2b76cfd8e601d588
Acked-by: Jie Luo <jluo@qti.qualcomm.com>
Signed-off-by: Niranjana Vishwanathapura <nvishwan@codeaurora.org>