ARM: OMAP4: hwmod_data: Name the common irq for McBSP ports

Use 'common' as name for the common irq number in hwmod data for the McBSP
ports. The same name already in use for OMAP2430, and OMAP3.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>