e1000e: fix unit hang during loopback test
e1000e: fix unit hang during loopback test

System would hang during execution of "ethtool -t <NIC>" for the same
reason that required flushing the descriptor rings. This fix disables
MULR for the loopback test to avoid the hang state.

Signed-off-by: Yanir Lubetkin <92610f7d2a881e373b47a48d6a67b431fc0c1511@intel.com>
Tested-by: Aaron Brown <4723df1d9a4136f7b76e1bf6434e33afc91d2139@intel.com>
Signed-off-by: Jeff Kirsher <87e35f5be20bb3e67f4ba6b86f5f6be3085b1b3a@intel.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs