netdev: bfin_mac: drop useless IRQF_SHARED from Blackfin EMAC interrupt

The IRQ used by the Blackfin EMAC is internal to the peripheral and cannot
be used to generate any other interrupt, so there is no point in marking it
as IRQF_SHARED.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>