tests: workqueue: increase stacks to allow coverage

Test was failing to build on some scenarios when coverage was enabled.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/tests/kernel/workq/work_queue/src/main.c b/tests/kernel/workq/work_queue/src/main.c
index f97f202..7c4b25d 100644
--- a/tests/kernel/workq/work_queue/src/main.c
+++ b/tests/kernel/workq/work_queue/src/main.c
@@ -63,8 +63,8 @@
 static int num_results;
 static int expected_poll_result;
 
-#define MSG_PROVIDER_THREAD_STACK_SIZE 0x400U
-#define MSG_CONSUMER_WORKQ_STACK_SIZE 0x400U
+#define MSG_PROVIDER_THREAD_STACK_SIZE 2048
+#define MSG_CONSUMER_WORKQ_STACK_SIZE 2048
 
 #define MSG_PROVIDER_THREAD_PRIO K_PRIO_PREEMPT(8)
 #define MSG_CONSUMER_WORKQ_PRIO K_PRIO_COOP(7)