msm: emac: Support for SGMII direct connection

Add the feature to support the SGMII direct connection without external
phy (EPHY) required for fsm9900 MTP board. In such case, the EMAC core
is directly connected to an on-board switch without an EPHY. The link
state can only be handled through the EMAC core internal SGMII PHY.

Change-Id: Iee782037e9a636c07ae1e896adec39f55e518024
Signed-off-by: Niranjana Vishwanathapura <nvishwan@codeaurora.org>