sys/print_stack_usage: update MIN_SIZE

Since fmt no longer has a significant advantage in stack consumption,
we need to bump the `MIN_SIZE` guard that prevents causing stack
overflows due to the printing of the stack consumption.

(cherry picked from commit 5b86848)

sys/test_utils/print_stack_usage/print_stack_usage.c

@@ -26,12 +26,7 @@
 #include <stdio.h>
 #endif
 
-#if MODULE_FMT
-/* fmt's `print_str()` needs very little stack. ~200 total was fine on Cortex-M. */
-# define MIN_SIZE   (THREAD_STACKSIZE_TINY)
-#else
 # define MIN_SIZE   (THREAD_STACKSIZE_TINY + THREAD_EXTRA_STACKSIZE_PRINTF)
-#endif
 
 void print_stack_usage_metric(const char *name, void *stack, unsigned max_size)
 {