It is confusing that mdio commands work and report phy id as
decimal value when mii is working with hex values.

For example:
ZynqMP> mdio list
gem:
21 - TI DP83867 <--> ethernet@ff0e0000
ZynqMP> mdio read ethernet@ff0e0000 0
Reading from bus gem
PHY at address 21:
0 - 0x1140
ZynqMP> mii dump 21 0
Incorrect PHY address. Range should be 0-31
...
ZynqMP> mii dump 15
0.     (1140)                 -- PHY control register --
  (8000:0000) 0.15    =     0    reset

U-Boot normally takes hex values that's why this patch is changing mdio
command to handle hex instead of changing mii command to handle decimal
values.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>