msm: vidc: Fix out of bound access in packetization

In hfi packetization, the driver was accessing
a variable of type struct hal_enable, by casting it to
struct hfi_enable. This resulted in an out of bound read
access.

Change-Id: Ic549a9cacc0cd726708628c49c9c5616ac57bb00
Signed-off-by: Arun Menon <avmenon@codeaurora.org>