[Keymap] Reduce NIBBLE oled_bongocat keymap size so it compiles (#13638)

keyboards/nullbitsco/nibble/keymaps/oled_bongocat/keymap.c

@@ -17,8 +17,6 @@
  */
 #include QMK_KEYBOARD_H
 #include "animation_frames.h"
-#include <stdio.h>
-
 
 enum layer_names {
   _BASE,
@@ -97,7 +95,6 @@ uint32_t anim_timer         = 0;
 uint32_t anim_sleep         = 0;
 uint8_t  current_idle_frame = 0;
 
-char wpm_str[10];
 bool tap_anim        = false;
 bool tap_anim_toggle = false;
 
@@ -161,8 +158,16 @@ static void render_anim(void) {
 void oled_task_user(void) {
     render_anim();
     oled_set_cursor(0, 14);
-    sprintf(wpm_str, ">%04d", get_current_wpm());
-    oled_write_ln(wpm_str, false);
+
+    uint8_t n = get_current_wpm();
+    char wpm_counter[6];
+    wpm_counter[5] = '\0';
+    wpm_counter[4] = '0' + n % 10;
+    wpm_counter[3] = '0' + (n /= 10) % 10;
+    wpm_counter[2] = '0' + n / 10 ;
+    wpm_counter[1] = '0';
+    wpm_counter[0] = '>';
+    oled_write_ln(wpm_counter, false);
 }
 #endif