sanitycheck: reduce verbosity when selecting specifc platforms

if we are using command line platform filter, no need to list every
other platform as excluded, we know that already.  Show only the
discards that apply to the selected platforms on the command line

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/scripts/sanitycheck b/scripts/sanitycheck
index 2f4e29b..805956d 100755
--- a/scripts/sanitycheck
+++ b/scripts/sanitycheck
@@ -2340,7 +2340,14 @@
         ts.discard_report(options.discard_report)
 
     if VERBOSE > 1 and discards:
+        # if we are using command line platform filter, no need to list every
+        # other platform as excluded, we know that already.
+        # Show only the discards that apply to the selected platforms on the
+        # command line
+
         for i, reason in discards.items():
+            if options.platform and i.platform.name not in options.platform:
+                continue
             debug(
                 "{:<25} {:<50} {}SKIPPED{}: {}".format(
                     i.platform.name,