msm: sde: fix unaligned access problem

debug offset comes from the user and can hold any value which can
cause unaligned access. This change fixes the unaligned access
problem on debug offset by properly aligning it.

Change-Id: Ie4de9a12433f6ffd568c6c86928b71a5537b0dff
Signed-off-by: Harsh Sahu <hsahu@codeaurora.org>