Enable RP2040 support for apa102 RGB LED driver (qmk#21908)

Author: drashna

drivers/led/apa102.c

@@ -24,7 +24,7 @@
 #    elif defined(PROTOCOL_CHIBIOS)
 #        include "hal.h"
 #        include "chibios_config.h"
-#        if defined(STM32F0XX) || defined(STM32F1XX) || defined(STM32F3XX) || defined(STM32F4XX) || defined(STM32L0XX) || defined(GD32VF103)
+#        if defined(STM32F0XX) || defined(STM32F1XX) || defined(STM32F3XX) || defined(STM32F4XX) || defined(STM32L0XX) || defined(GD32VF103) || defined(MCU_RP)
 #            define APA102_NOPS (100 / (1000000000L / (CPU_CLOCK / 4))) // This calculates how many loops of 4 nops to run to delay 100 ns
 #        else
 #            error APA102_NOPS configuration required