ARM: dts: am335x-bone-common: add collision and carrier sense pinmux

Added pin mux definitions for collision and carrier sense errors coming
from the ethernet phy. Without these two signals the MAC ends up ignoring
the errors detected by the PHY which end up causing a lower throughput
problem when the phy is in half duplex mode such as connected through a hub.

Fixes: 2ba35493 (ARM: dts: am335x-bone*: add DT for BeagleBone Black)
Cc: Koen Kooi <koen@dominion.thruhere.net>
Cc: Tom Rini <trini@ti.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: <stable@vger.kernel.org> # v3.13+
Signed-off-by: Schuyler Patton <spatton@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>