We allocate efx_channel structures with kzalloc() so we don't need to
zero-initialise individual fields in efx_probe_channel().  Further,
this function will be called again during DMA ring resizing and we
should not reset any statistics then.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NShradha Shah <sshah@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>