Even the driver doesn't do anything with the clk source for SGMII
ports it needs to be enabled by doing a devm_clk_get(), if there is
a clk source in DT.

Fixes: 0db01097 ('xgene: Don't fail probe, if there is no clk resource for SGMII interfaces')
Signed-off-by: NThomas Bogendoerfer <tbogendoerfer@suse.de>
Tested-by: NLaura Abbott <labbott@redhat.com>
Acked-by: NIyappan Subramanian <isubramanian@apm.com>
Tested-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>