pxa168_eth: remove unneeded null check

"pep->pd" isn't checked consistently in this function.  For example it's
dereferenced unconditionally on the next line after the end of the if
condition.  This function is only called from pxa168_eth_probe() and
pep->pd is always non-NULL so I removed the check.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>