platform/x86/intel/ifs: Add missing kernel-doc entry

Document the test_num member of struct ifs_data.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NJithu Joseph <jithu.joseph@intel.com>
Signed-off-by: NBorislav Petkov (AMD) <bp@alien8.de>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/lkml/774fd22a-aaee-758d-8195-77bac783ecbc@infradead.org/

drivers/platform/x86/intel/ifs/ifs.h

@@ -208,6 +208,7 @@ union ifs_status {
  * @status: it holds simple status pass/fail/untested
  * @scan_details: opaque scan status code from h/w
  * @cur_batch: number indicating the currently loaded test file
+ * @test_num: number indicating the test type
  */
 struct ifs_data {
 	int	integrity_cap_bit;