NET: MIPS: Lantiq: Return value of request_irq was not handled gracefully

NET: MIPS: Lantiq: Return value of request_irq was not handled gracefully

The return values of request_irq() were not checked leading to the following
error message.

drivers/net/ethernet/lantiq_etop.c: In function 'ltq_etop_hw_init':
drivers/net/ethernet/lantiq_etop.c:368:15: warning: ignoring return value of 'request_irq', declared with attribute warn_unused_result
drivers/net/ethernet/lantiq_etop.c:377:15: warning: ignoring return value of 'request_irq', declared with attribute warn_unused_result

Signed-off-by: John Crispin <blogic@openwrt.org>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3275/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>