drm/msm/a6xx: Fix GMU firmware parser

drm/msm/a6xx: Fix GMU firmware parser

Current parser logic for GMU firmware assumes a dword aligned payload
size for every block. This is not true for all GMU firmwares. So, fix
this by using correct 'size' value in the calculation for the offset
for the next block's header.

Fixes: c6ed04f856a4 ("drm/msm/a6xx: A640/A650 GMU firmware path")
Signed-off-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
Acked-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/674040/
Message-ID: <20250911-assorted-sept-1-v2-2-a8bf1ee20792@oss.qualcomm.com>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>