drm/msm: msm_gem_vma.c: fix all kernel-doc warnings

drm/msm: msm_gem_vma.c: fix all kernel-doc warnings

Correct or add kernel-doc comments to eliminate all warnings:

Warning: ../drivers/gpu/drm/msm/msm_gem_vma.c:96 expecting prototype for
 struct msm_vma_op. Prototype was for struct msm_vm_op instead

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/695679/
Link: https://lore.kernel.org/r/20251219184638.1813181-18-rdunlap@infradead.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>