In case of a partition number at the profile only an existing partition can be mounted.

Signed-off-by: Thomas Mittelstaedt <thomas.mittelstaedt@de.bosch.com>

tools/mountimage

@@ -649,6 +649,9 @@ local mbind rootmnt
     mdevice=
   elif test "$idtype" = "PARTNR"; then
     mdevice="${devicep}${idvalue}"
+    if [ ! -b "$mdevice" ]; then
+      mdevice=
+    fi
   else
     print_error_line "Can't understand $\"$descr\"\n"
     exit 1