smc91c92_cs:
Fix the problem that lan & modem does not work simultaneously
in the Megahertz multi-function card.
We need to write MEGAHERTZ_ISR to retrigger interrupt.
Signed-off-by: Ken Kawasaki <ken_kawasaki@spring.nifty.jp> Signed-off-by: David S. Miller <davem@davemloft.net>