ARM: OMAP2+: Only probe SDMA via ti-sysc if configured in dts

We still have some SDMA probing using omap_device_build() for the
arch/arm/plat-omap/dma.c part that the dmaengine driver then uses.

So we still need to ensure that omap_device_build() works even if we
probe and manage the dmaengine driver via ti-sysc. And we don't want
to call dev_pm_domain_set() as otherwise we'd also have omap_device
try to manage the hardware in addition to ti-sysc.

Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>