net/designware: Try configuring phy on each dw_eth_init

net/designware: Try configuring phy on each dw_eth_init

Phy autonegotiation works only when the ethernet cable is plugged in.
Since the phy was configured only at the init time, a plugged in cable
was necessary to initialize the phy properly.

This patch keeps a flag to check if the phy initialization has
succeeded, and calls configure_phy routine at every init if this flag
reports otherwise.

Signed-off-by: Vipin Kumar <vipin.kumar@st.com>
Signed-off-by: Amit Virdi <amit.virdi@st.com>