soc: qcom: secure_buffer: Fix the parameter passing to dmac_flush_range

For "chunk_list + chunk_list_len", if the chunk_list is type of u32*,
the chunk_list_len will be 4 * of original size. So we flushed a wrong
area size. In some condition like we enabled CONFIG_DEBUG_PAGEALLOC, it
may flush out of page bound of the invalid pte page.

Fix it by manually convert it as void* when doing the addition.

CRs-Fixed: 2309993
Change-Id: I2b88d78ba73d9904fa2bf6106937001715b6037f
Signed-off-by: Zhenhua Huang <zhenhuah@codeaurora.org>