net: thunderx: Fix OOPs with ethtool --register-dump

net: thunderx: Fix OOPs with ethtool --register-dump

commit 1423661fed2c40d6d71b5e2e3aa390f85157f9d5 upstream.

The ethtool_ops .get_regs function attempts to read the nonexistent
register NIC_QSET_SQ_0_7_CNM_CHG, which produces a "bus error" type
OOPs.

Fix by not attempting to read, and removing the definition of,
NIC_QSET_SQ_0_7_CNM_CHG.  A zero is written into the register dump to
keep the layout unchanged.

Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>