[nrf noup] samples: basic: blinky: rename SDP to HPF

nrf-squash! [nrf noup] samples: basic: blinky: add eGPIO tests configuration

Change names SDP and eGPIO to new names: HFP and hpf_gpio.

Signed-off-by: Magdalena Pastula <[email protected]>
(cherry picked from commit 1e01213)

Author: magp-nordic

samples/basic/blinky/boards/nrf54l15dk_nrf54l15_cpuapp_egpio.overlay renamed to samples/basic/blinky/boards/nrf54l15dk_nrf54l15_cpuapp_hpf_gpio.overlay

@@ -5,5 +5,5 @@
  */
 
 &led0 {
-	gpios = <&egpio 9 GPIO_ACTIVE_HIGH>;
+	gpios = <&hpf_gpio 9 GPIO_ACTIVE_HIGH>;
 };