common: miiphyutil: no need to check name of mii_dev

The entry name of mii_dev is an array not pointer, so
no need to check.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>