mdss: pp: fix incorrect base addr len in csc setup

As a part of VG pipe setup the post-proc driver
constructs the color space conversion table. This involves
programming the hardware using values from a static CSC
conversion table in the driver. Since MMSS blocks remain 32-bit
addressable the iterator for hardware registers used in
post-proc driver should move ahead in
increments of 32-bit to program these values into mdss-pp
registers and not the width of a pointer in memory.
Use 32-bit to fix incorrect CSC programming of the hardware.

CRs-Fixed: 642481
Change-Id: I49b4b008c1ebb1a8032603fe2f16b1fe893d91ff
Signed-off-by: Manoj Rao <manojraj@codeaurora.org>