ARM: orion5x: Revert commit 4904dbda.

It is not valid for orion5x to use mac_pton().

First of all, the orion5x buffer is not NULL terminated.  mac_pton()
has no business operating on non-NULL terminated buffers because
only the caller can know that this is valid and in what manner it
is ok to parse this NULL'less buffer.

Second of all, orion5x operates on an __iomem pointer, which cannot
be dereferenced using normal C pointer operations.  Accesses to
such areas much be performed with the proper iomem accessors.

Fixes: 4904dbda

 ("ARM: orion5x: use mac_pton() helper")
Signed-off-by: David S. Miller <davem@davemloft.net>