uboot-phytec

MLK-23871 imx: Increase ENET PHY negotiation timeout for all iMX

Found the default negotiation timeout 4s is not enough in our test
environment. Increase it to 20s to avoid timeout.

Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Fugang Duan <fugang.duan@nxp.com>
(cherry picked from commit e7252f1bd9f0034bc05bfab5c088d82ab2112062)