ARM: OMAP2+: Populate legacy resources for dma and smartreflex

We can populate the legacy resources needed by dma and smartreflex
from device tree in omap_device_build().

There should be no need to do this for other devices, and eventually
these two remaining users will be gone too. The legacy dma will be
dropped when the remaining users have been converted to use the
dmaengine driver, and smartreflex can now become just a regular
device driver with a few pdata callbacks.

This is needed in order to remove remaining device dma, irq and io
resources from the interconnect code.

And while at it, let's simplify things by removing otherwise
unused omap_device_build_ss() as we will never call it for more
than one hwmod.

Cc: "Benoît Cousson" <bcousson@baylibre.com>
Cc: Lokesh Vutla <lokeshvutla@ti.com>
Cc: Nishanth Menon <nm@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>