ARM: OMAP2+: devices: Do not print error when DMIC hwmod lookup fails

It means that the SoC does not have DMIC IP.

Reported-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>