drm/msm: fix unwanted shift in blob property data

While trying to access the blob data, the pointer is seen in
the first 8 bytes causing the unwanted shift. This change
fixes that and returns the pointer data directly.

Change-Id: I366eb9ee1daf9fe39654f6e5000858fe600ecb51
Signed-off-by: Samantha Tran <samtran@codeaurora.org>