ARM: OMAP2+: Parse module IO range from dts for legacy "ti,hwmods" support

When removing legacy platform data for IO ranges for the hwmod
interconnect code, we still need to support the "ti,hwmods"
property.

And as we're going to use a generic sysc device driver to handle the
interconnect target instances, we can parse the information needed
for legacy "ti,hwmods" IO range from the dts. It's always the first
range the interconnect target module provides.

Note that we want to parse the range instead of the first child
device IO regs as the child device may not always be defined.

The child IP device node may not exist in cases where there is no
driver binding for the device, or when the child IP block may not
even be functional for some SoC revisions. But the IO range of the
interconnect target module is always known.

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