net: reduce boot latency on QE UEC based boards

net: reduce boot latency on QE UEC based boards

actually polling for PHY autonegotiation to finish enables us to remove the
5 second boot prompt latency present on QE based boards.

call to qe_set_mii_clk_src in init_phy, and mv call to init_phy from
uec_initialize to uec_init by Joakim Tjernlund; autonegotiation wait
code shamelessly stolen from tsec driver.

also rm unused CONFIG_RMII_MODE code.

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>