soc: qcom: pil-mss: free the allocated area during ramdump

During ramdump collection, the modem subsystem needs the MBA to be
loaded again. The allocation of memory done during that time is not
currently being freed and as a result, the common CMA area is getting
filled up.
Explicitly free the allocation area before bringing down the subsystem.

CRs-Fixed: 686515
Change-Id: I28b0ed381c2ad5ee1fcfacea4913184167af9815
Signed-off-by: Taniya Das <tdas@codeaurora.org>