drm/i915/gvt: clean up kernel-doc in gtt.c

Fix kernel-doc warnings in gtt.c:

gtt.c:1152: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * Check if can do 2M page
gtt.c:1152: warning: missing initial short description on line:
 * Check if can do 2M page
gtt.c:2209: warning: expecting prototype for intel_vgpu_emulate_gtt_mmio_read(). Prototype was for intel_vgpu_emulate_ggtt_mmio_read() instead

Fixes: a752b070 ("drm/i915/gvt: Fix function comment doc errors")
Fixes: 2707e444

 ("drm/i915/gvt: vGPU graphics memory virtualization")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Cc: Colin Xu <colin.xu@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: intel-gvt-dev@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20211003052334.15764-1-rdunlap@infradead.org


Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>