ARM: OMAP2+: Remove legacy device creation for McPDM and DMIC

McPDM and DMIC only available on OMAP4/5 which no longer boots in legacy
mode.
The code to create the devices in legacy mode can be removed.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>