The table grows quickly during debug/development effort when
multiple RAS errors are injected. Allow to avoid this by setting
table header back to empty if needed.

v2: Switch to debugfs entry instead of load time parameter.
Signed-off-by: NAndrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by: NTao Zhou <tao.zhou1@amd.com>
Reviewed-by: NGuchun Chen <guchun.chen@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>