tests: increase stack size on test_errno

The stacks are overrun on ARM.

Change-Id: Ic5f1555b138a732e409c92cff716278b33dfce5d
Signed-off-by: Benjamin Walsh <[email protected]>

Author: benwrs

tests/legacy/kernel/test_errno/src/main.c

@@ -20,7 +20,7 @@
 
 #define N_FIBERS 2
 
-#define STACK_SIZE 256
+#define STACK_SIZE 384
 static __stack char stacks[N_FIBERS][STACK_SIZE];
 
 static int errno_values[N_FIBERS + 1] = {