uboot-imx

ARM: uniphier: remove CONFIG_ARP_TIMEOUT define

I no longer see the problem claimed in the comment block.  Rather,
the 0.5 msec timeout seems too short for some TFTP servers.

Drop the CONFIG_ARM_TIMEOUT to fall back to the 5 sec timeout.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>