xen/arm: gic-v3: Fix redistributor wakeup polling

gicv3_enable_redist() clears GICR_WAKER.ProcessorSleep and then waits for
GICR_WAKER.ChildrenAsleep to clear, as required after waking a
redistributor.

However, the polling loop currently uses "while ( timeout )". Since
timeout is initially false, the loop runs only once unless the timeout
path has already been reached. As a result, Xen can continue before the
redistributor has completed wakeup.

Use an unconditional loop, matching the surrounding timeout/break pattern,
so the code polls until either ChildrenAsleep is clear or the deadline is
reached.

While there, also fix the timeout message. This path polls
GICR_WAKER.ChildrenAsleep, not an RWP bit, so "RWP timeout" is misleading.

Fixes: bc183a0235 ("xen/arm: Add support for GIC v3")
Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Mykola Kvach <mykola_kvach@epam.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>
Release-Acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
(cherry picked from commit 941fdfc03e)

xen/arch/arm/gic-v3.c

@@ -704,11 +704,11 @@ static int gicv3_enable_redist(void)
         }
         cpu_relax();
         udelay(1);
-    } while ( timeout );
+    } while ( 1 );
 
     if ( timeout )
     {
-        dprintk(XENLOG_ERR, "GICv3: Redist enable RWP timeout\n");
+        dprintk(XENLOG_ERR, "GICv3: Redist wakeup timeout\n");
         return 1;
     }