net: bcmgenet: correct MIB access of UniMAC RUNT counters

net: bcmgenet: correct MIB access of UniMAC RUNT counters

[ Upstream commit 1ad3d225e5a40ca6c586989b4baaca710544c15a ]

The gap between the Tx status counters and the Rx RUNT counters is now
being added to allow correct reporting of the registers.

Fixes: 1c1008c793fa ("net: bcmgenet: add main driver file")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>