[nrf fromtree] boards: nordic: nrf54l15dk: Rename the board common file

Use the rather logical convention for the name that is applied to other
Nordic boards: <board>_common.dtsi for definitions that are common to
the board itself (LEDs, buttons, etc).

Signed-off-by: Carles Cufi <[email protected]>
(cherry picked from commit 1b84958)

Author: carlescufi

boards/nordic/nrf54l15dk/nrf54l15_cpuapp_common.dtsi

@@ -7,7 +7,7 @@
 /* This file is common to the secure and non-secure domain */
 
 #include <nordic/nrf54l15_cpuapp.dtsi>
-#include "nrf54l15dk_nrf54l15-common.dtsi"
+#include "nrf54l15dk_common.dtsi"
 
 / {
 	chosen {

boards/nordic/nrf54l15dk/nrf54l15dk_nrf54l15-common.dtsi renamed to boards/nordic/nrf54l15dk/nrf54l15dk_common.dtsi

@@ -6,7 +6,7 @@
 
 /dts-v1/;
 #include <nordic/nrf54l15_cpuflpr.dtsi>
-#include "nrf54l15dk_nrf54l15-common.dtsi"
+#include "nrf54l15dk_common.dtsi"
 
 / {
 	model = "Nordic nRF54L15 DK nRF54L15 FLPR MCU";