platform/x86/intel/ifs: Fix SBAF title underline length

In commit # 0a3e4e9 ("platform/x86/intel/ifs: Add SBAF test image
loading support"), the documentation for "Structural Based Functional
Test at Field (SBAF)" had an incomplete underline. This resulted in the
following build warning:

Documentation/arch/x86/ifs:2: drivers/platform/x86/intel/ifs/ifs.h:131: WARNING: Title underline too short.

Fix it by extending the dotted lines to match the length of the title.

Fixes: 0a3e4e9 ("platform/x86/intel/ifs: Add SBAF test image loading support")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/lkml/20240820134354.2aec355d@canb.auug.org.au/T/#u
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Jithu Joseph <jithu.joseph@intel.com>
Link: https://lore.kernel.org/r/20240823184337.2923179-1-sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Author: Kuppuswamy Sathyanarayanan

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

@@ -129,7 +129,7 @@
  *
  *
  * Structural Based Functional Test at Field (SBAF):
- * ------------------------------------------------
+ * -------------------------------------------------
  *
  * SBAF is a new type of testing that provides comprehensive core test
  * coverage complementing Scan at Field (SAF) testing. SBAF mimics the