Remove useless "ifdef KEYBOARD_*" (#20078)

Co-authored-by: Nick Brassel <nick@tzarc.org>

keyboards/avalanche/avalanche.c

@@ -1,7 +1,7 @@
 // Copyright 2022 Vitaly Volkov (@vlkv)
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-#include "avalanche.h"
+#include "quantum.h"
 
 #ifdef ENCODER_ENABLE
 bool encoder_update_kb(uint8_t index, bool clockwise) {

keyboards/avalanche/avalanche.h

@@ -1,16 +0,0 @@
-// Copyright 2022 Vitaly Volkov (@vlkv)
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-#pragma once
-
-#ifdef KEYBOARD_avalanche_v1
-    #include "v1.h"
-#elif KEYBOARD_avalanche_v2
-    #include "v2.h"
-#elif KEYBOARD_avalanche_v3
-    #include "v3.h"
-#elif KEYBOARD_avalanche_v4
-    #include "v4.h"
-#endif
-
-#include "quantum.h"

keyboards/avalanche/v1/v1.c

@@ -1,4 +0,0 @@
-// Copyright 2022 Vitaly Volkov (@vlkv)
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-#include "avalanche.h"

keyboards/avalanche/v1/v1.h

@@ -3,8 +3,6 @@
 
 #pragma once
 
-#include "avalanche.h"
-
 #include "quantum.h"
 
 #define L__ KC_NO

keyboards/avalanche/v2/v2.c

@@ -1,4 +0,0 @@
-// Copyright 2022 Vitaly Volkov (@vlkv)
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-#include "avalanche.h"

keyboards/avalanche/v2/v2.h

@@ -3,8 +3,6 @@
 
 #pragma once
 
-#include "avalanche.h"
-
 #include "quantum.h"
 
 #define L__ KC_NO

keyboards/avalanche/v3/v3.c

@@ -1,4 +0,0 @@
-// Copyright 2022 Vitaly Volkov (@vlkv)
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-#include "avalanche.h"

keyboards/avalanche/v3/v3.h

@@ -3,8 +3,6 @@
 
 #pragma once
 
-#include "avalanche.h"
-
 #include "quantum.h"
 
 #define L__ KC_NO

keyboards/avalanche/v4/v4.c

@@ -1,7 +1,7 @@
 // Copyright 2022 Vitaly Volkov (@vlkv)
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-#include "avalanche.h"
+#include "v4.h"
 
 #ifdef OLED_ENABLE
 oled_rotation_t oled_init_kb(oled_rotation_t rotation) {

keyboards/avalanche/v4/v4.h

@@ -3,8 +3,6 @@
 
 #pragma once
 
-#include "avalanche.h"
-
 #include "quantum.h"
 
 #define L__ KC_NO