iommu: msm: Fix incorrect address list preparation

During secure map, the scatterlist is converted into a
simple array of 1MB chunk addresses. This array is then
passed to TZ. The code which does this incorrectly
increments physical base address each time, besides
adding chunk size. Fix this.

Change-Id: I82b3b4eb3b008af14450873b8d34867df81e6ca8
Signed-off-by: Shiraz Hashim <shashim@codeaurora.org>