ARM: dts: msm: mpq8092: Add node for the memory hole

The memory map for mpq8092 has a region of memory that does not
belong to Linux. Add that information into the device tree.

Change-Id: I0287b74e538cc7cc262deaa1fe0f6abe00b7d6f8
Signed-off-by: Srinivas Ramana <sramana@codeaurora.org>