In OMAP4, there is only one irq line for TX and RX paths. Use
the correct irq line to avoid errors at runtime.

Also, request irq line only once (instead of requesting for TX
and RX).
Signed-off-by: NJorge Eduardo Candelaria <jorge.candelaria@ti.com>
Acked-by: NJarkko Nikula <jhnikula@gmail.com>
Acked-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NLiam Girdwood <lrg@slimlogic.co.uk>