ARM: dts: DRA7: Add common IPU and DSP nodes

ARM: dts: DRA7: Add common IPU and DSP nodes

The DRA7xx family of SOCs have two IPUs and upto two DSP
processor subsystems in general. The IPU processor subsystem
contains dual-core ARM Cortex-M4 processors, while the DSP
processor subsystem is based on the TI's standard TMS320C66x
DSP CorePac core. The IPUs are very similar to those on OMAP5.

Two IPUs and one DSP processor subsystems is the most common
configuration. The processor device DT nodes have been added
for these processor subsystems, with the internal memories
added through 'reg' and 'reg-names' properties. The IPUs only
have an L2 RAM, whereas the DSPs have L1P, L1D and L2 RAM
memories.

NOTE:
1. The nodes do not have any mailboxes, timers or CMA regions
   assigned, they should be added in the respective board dts
   files.
2. The nodes haven been disabled by default and the enabling
   of these nodes is also left to the respective board dts
   files.

Signed-off-by: Suman Anna <s-anna@ti.com>
[t-kristo@ti.com: convert to ti-sysc support from legacy hwmod]
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>