msm: pil: Don't free dynamic allocations

We don't want to free the dynamic allocations for an image's
relocatable area because we can't guarantee there won't be
internal fragmentation. Reuse the region if it has already been
allocated and be sure to not free it when reinitializing the
memory map for an image.

Change-Id: Ibb7402a1a418d455572bfa6111336b3cfa312640
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>