kvm/ppc/mpic: remove default routes from documentation

The default routes were removed from the code during patchset
respinning, but were not removed from the documentation.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

Documentation/virtual/kvm/devices/mpic.txt

@@ -50,7 +50,4 @@ IRQ Routing:
   regard to any subdivisions in chip documentation such as "internal"
   or "external" interrupts.
 
-  Default routes are established for these pins, with the GSI being equal
-  to the pin number.
-
   Access to non-SRC interrupts is not implemented through IRQ routing mechanisms.