net: cs89x0: includecheck fix for cs89x0.c

fix the following 'make includecheck' warning:

  drivers/net/cs89x0.c: asm/irq.h is included more than once.

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>