Fix the following coccicheck warning:
./drivers/gpu/drm/msm/msm_debugfs.c: 132: 0-23: WARNING: shrink_fops
should be defined with DEFINE_DEBUGFS_ATTRIBUTE

Use DEFINE_DEBUGFS_ATTRIBUTE rather than DEFINE_SIMPLE_ATTRIBUTE for
debugfs files.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Changcheng Deng <deng.changcheng@zte.com.cn>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20211221144234.480618-1-deng.changcheng@zte.com.cnSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>