ARM: dts: omap4-panda-common:: Add system timers to DSP and IPU

ARM: dts: omap4-panda-common:: Add system timers to DSP and IPU

The BIOS System Tick timers have been added for the IPU and DSP
remoteproc devices on all the OMAP4-based Panda boards. The
following DMTimers are chosen:
	IPU : GPT3 (SMP-mode)
	DSP : GPT5

IPU has two Cortex-M3 processors, and is currently expected to be
running in SMP-mode, so only a single timer suffices to provide
the BIOS tick timer. An additional timer should be added for the
second processor in IPU if it were to be run in non-SMP mode. The
timer value also needs to be unique from the ones used by other
processors so that they can be run simultaneously.

The timers are optional, but are mandatory to support device
management features such as power management and watchdog support.
The above are added to successfully boot and execute firmware images
configured with the respective timers, images that use internal
processor subsystem timers are not affected. The timers can be
changed or removed as per the system integration needs, alongside
equivalent changes on the firmware side.

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>