[Silabs] Reduce timer stack depth (#41587) * Reduce timer stack * define in bytes intead of words

diff --git a/examples/platform/silabs/FreeRTOSConfig.h b/examples/platform/silabs/FreeRTOSConfig.h
index 7eda14c..29f56a6 100644
--- a/examples/platform/silabs/FreeRTOSConfig.h
+++ b/examples/platform/silabs/FreeRTOSConfig.h

@@ -183,7 +183,7 @@
 // Keep the timerTask at the highest prio as some of our stacks tasks leverage eventing with timers.
 #define configTIMER_TASK_PRIORITY (55) /* Highest priority */
 #define configTIMER_QUEUE_LENGTH (10)
-#define configTIMER_TASK_STACK_DEPTH (1024)
+#define configTIMER_TASK_STACK_DEPTH (1280 / sizeof(StackType_t))
 
 #ifdef SLI_SI91X_MCU_INTERFACE
 #ifdef __NVIC_PRIO_BITS