Remove more cruft in keyboard files (#14288)

keyboards/cu75/cu75.c

@@ -28,12 +28,12 @@ void matrix_init_kb(void)
     audio_init();
     PLAY_SONG(test_sound);
     // Fix port B5
-    cbi(DDRB, 5);
-    sbi(PORTB, 5);
+    setPinInput(B5);
+    writePinHigh(B5);
 #else
     // If we're not using the audio pin, drive it low
-    sbi(DDRC, 6);
-    cbi(PORTC, 6);
+    setPinOutput(C6);
+    writePinLow(C6);
 #endif
 #ifdef ISSI_ENABLE
     issi_init();

keyboards/cu75/cu75.h

@@ -1,26 +1,10 @@
 #ifndef CU75_H
 #define CU75_H
 
-/* if the kb.h file exists (because we're running from qmkbuilder) include it */
-#ifdef __has_include
-#if __has_include("kb.h")
-#include "kb.h"
-#endif
-#endif
-
 #include "quantum.h"
 #include "matrix.h"
 #include <avr/sfr_defs.h>
 
-#ifndef cbi
-#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
-#endif
-
-#ifndef sbi
-#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
-#endif
-
-
 typedef struct RGB_Color {
     uint16_t red;
     uint16_t green;