remoteproc/omap: add support to parse internal memories from DT

The OMAP remoteproc driver has been enhanced to parse and store
the kernel mappings for different internal RAM memories that may
be present within each remote processor IP subsystem. Different
devices have varying memories present on current SoCs. The current
support handles the L2RAM for all IPU devices on OMAP4+ SoCs and
L2RAM for all DSP devices on DRA7xx SoCs. The DSPs on OMAP4/OMAP5
only have Unicaches and do not have any L1 or L2 RAM memories. The
OMAP remoteproc binding is also updated to match the parsing logic
based on names.

IPUs are expected to have the L2RAM at a fixed device address of
0x20000000, based on the current limitations on Attribute MMU
configurations. The device addresses for the DSP memories are
computed based on relative addressing logic.

NOTE:
The current logic doesn't handle the parsing of L1P or L1D memories
on DRA7 DSPs, but it can be easily added if needed in the future.

Signed-off-by: Suman Anna <s-anna@ti.com>