soc: qcom: memory_dump_v2: fix the end address passed to dmac_flush_range()

Fix the pointer arithmetic to ensure the end address passed in
dmac_flush_range() call doesn't go beyond the end of the
msm_dump_table.

Change-Id: Ia80ac1d6ffddb8a5313a3e106020d7e0c633b054
Signed-off-by: Pratik Patel <pratikp@codeaurora.org>