drm/msm/msm_gem: Demote kernel-doc abuses

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/msm/msm_gem.c:364: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 drivers/gpu/drm/msm/msm_gem.c:763: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst

Cc: Rob Clark <robdclark@gmail.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: linux-arm-msm@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: freedreno@lists.freedesktop.org
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210602143300.2330146-13-lee.jones@linaro.orgReviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/msm_gem.c

@@ -364,7 +364,7 @@ static void del_vma(struct msm_gem_vma *vma)
 	kfree(vma);
 }
 
-/**
+/*
  * If close is true, this also closes the VMA (releasing the allocated
  * iova range) in addition to removing the iommu mapping.  In the eviction
  * case (!close), we keep the iova allocated, but only remove the iommu
@@ -768,7 +768,7 @@ void msm_gem_purge(struct drm_gem_object *obj)
 			0, (loff_t)-1);
 }
 
-/**
+/*
  * Unpin the backing pages and make them available to be swapped out.
  */
 void msm_gem_evict(struct drm_gem_object *obj)