libsel4platsupport: Update ltimer calls

Following from the ltimer IRQ allocation and callback changes, this
commits updates the ltimer calls to reflect the changes. This is meant
to be band-aid fix to just get things compiling until the deprecation of
the timer library in libsel4platsupport.

libsel4platsupport/src/timer.c

diff --git a/libsel4platsupport/src/timer.c b/libsel4platsupport/src/timer.c
index fd48c1e..a25edc4 100644
--- a/libsel4platsupport/src/timer.c
+++ b/libsel4platsupport/src/timer.c
@@ -58,7 +58,6 @@
             /* mask the bit out of the badge */
             badge &= ~BIT(irq);
             if (timer->to.irqs[i].irq.type != PS_NONE) {
-                ltimer_handle_irq(&timer->ltimer, &timer->to.irqs[i].irq);
                 int error = seL4_IRQHandler_Ack(timer->to.irqs[i].handler_path.capPtr);
                 if (error) {
                     ZF_LOGE("Failed to ack irq %lu, error %d", irq, error);
@@ -167,7 +166,7 @@
     }
 
     if (!error)  {
-        error = ltimer_default_init(&timer->ltimer, ops);
+        error = ltimer_default_init(&timer->ltimer, ops, NULL, NULL);
     }
     return error;
 }