mv643xx_eth: Add Rx Discard and Rx Overrun statistics
mv643xx_eth: Add Rx Discard and Rx Overrun statistics

These statistics helped me a lot while searching who is losing
packets in my setup.
I added these stats to MIB group since they are very similar,
but just in other registers.
I have tested this patch on 88F6281 SoC.

Signed-off-by: Paulius Zaleckas <c59c332b61c0401f49d806e6931557f8bdeeaad8@gmail.com>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas