soc: qcom: pil: Align to SZ_4K by default

Align to 1MB will cause dma allocation failure if the carvout
pil region is smaller than 1MB. Instead, align the size to 4K
by default.

Change-Id: I6ecf34eb58b837251e50c42238d29389b4edbd1d
Signed-off-by: Runmin Wang <runminw@codeaurora.org>