samples: blinky_pwm: enable pwm_leds in rpi_pico overlay

Twister skips the blinky_pwm sample for the rpi_pico board because the
pwm-leds compatible is disabled.

Enable /pwm_leds node so that twister build the sample for the rpi_pico
board.

Signed-off-by: Torsten Rasmussen <[email protected]>

Author: tejlmand

samples/basic/blinky_pwm/boards/rpi_pico.overlay

@@ -1,3 +1,7 @@
+&{/pwm_leds} {
+	status = "okay";
+};
+
 &pwm_led0 {
 	status = "okay";
 };