sh_eth: add IRQ flags to 'struct sh_eth_cpu_data'

The driver supports some SH and SH-Mobile SOCs. There are SOCs with two or more
Ethernet devices, for these we need to pass IRQF_SHARED to request_irq().  Add
the 'irq_flags' field to the 'struct sh_eth_cpu_data' instead of #ifdef'fery.

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
[Sergei: properly aligned request_irq() call continuation line, reworded the
changelog, reworded the subject, changing the prefix.]
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>