soc: qcom: memory_dump: Add support for generic memory dump entry allocator

Currently, each dump table entry is being registered in several
places in the kernel. Add centralized support in memory dump
driver to parse the device tree to register and allocate dump
table entries. We rely on CMA memory pool to allocate memory
for the dump entries. Clients can either use the generic approach
or configure the dump table entries independently using the
existing framework.

Change-Id: I313d90a4fe3ce3e2f24ddb8f509318c1590c1c7e
Signed-off-by: Satyajit Desai <sadesai@codeaurora.org>