net: ethernet: ti: cpsw: remove intr dbg msg from poll handlers

At poll handler no possibility to figure out which network device is
handling packets, as cpdma channels are common for both network
devices in dual_emac mode. Currently, the messages are printed only
for one device, in fact, there is two. This print msg is incorrect
and seems is not very useful, so drop it from poll handler.

Reviewed-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>