ARM: OMAP4: twl-common: Support for additional devices on i2c1 bus

On OMAP4 the i2c1 bus is dedicated for the PMIC and audio related devices.
Manufacturers can opt to use different codec than twl6040 and also can add
audio related IC to the bus (external amplifier for example on SDP4430).

Make it possible to add different set of additional devices to i2c1 bus on
OMAP4 boards.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
[tony@atomide.com: updated for removal of irqs.h]
Signed-off-by: Tony Lindgren <tony@atomide.com>