xen/arm: timer: Don't warn if the timer interrupts are high-level

The commit 61d6a84 "xen: arm: Warn if timer interrupts are not level
triggered" added a check to ensure the timer interrupts are level.

Although, the check is only done on low-level interrupts. This will
result to a strange warning on platform using high-level ("WARNING [..]
IRQ is not level triggered").

As high-level interrupt is valid, don't warn on both high-level and
low-level interrupt.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

xen/arch/arm/time.c

@@ -217,7 +217,7 @@ static void check_timer_irq_cfg(unsigned int irq, const char *which)
      * The interrupt controller driver will update desc->arch.type with
      * the actual type which ended up configured in the hardware.
      */
-    if ( desc->arch.type & DT_IRQ_TYPE_LEVEL_LOW )
+    if ( desc->arch.type & DT_IRQ_TYPE_LEVEL_MASK )
         return;
 
     printk(XENLOG_WARNING