ci(coverity): fix badly-parsed `--jobs` argument

Because there's no longer whitespace between `--jobs` and its sanitised
value, the shell interprets the quotes as part of the argument.

Instead, just use `-j`.

Change-Id: I1d0d5f4a5993f333ffb96aab48189615305e66b5
Signed-off-by: Chris Kay <chris.kay@arm.com>
diff --git a/script/tf-coverity/common-def.sh b/script/tf-coverity/common-def.sh
index b4509e6..2b46130 100644
--- a/script/tf-coverity/common-def.sh
+++ b/script/tf-coverity/common-def.sh
@@ -44,7 +44,7 @@
     debug="DEBUG=1"
     [ -n "$release" ] && debug=""
 
-    echo " --jobs=${jobs@Q} $debug -s "
+    echo " -j ${jobs@Q} $debug -s "
 }
 
 # Check if execution environment is ARM's jenkins (Jenkins running under ARM