hw/net/e1000: Don't use *_to_cpup()

Don't use *_to_cpup() to do byte-swapped loads; instead use
ld*_p() which correctly handle misaligned accesses.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Dmitry Fleytman &lt;dmitry@daynix.com <mailto:dmitry@daynix.com&gt;>
Message-id: 1466097446-981-6-git-send-email-peter.maydell@linaro.org