net: arc: trivial: Replace comma with a semicolon

Fix a typo in the driver, replace comma with a semicolon at the end
of statement. While using comma is a legal C here and probably does
not even generate compiler warning, it was unlikely the intention.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Caesar Wang <wxt@rock-chips.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: David S. Miller <davem@davemloft.net>