boards: nordic: nrf54l15dk: update lfxo capacitance

Update the lfxo node load-capacitance-femtofarad to
match the chosen external lfxo on the nRF54L15-DK design.
Previous stray capacitance value was incorrect, which
resulted in a too low load capacitance.

Signed-off-by: Håkon Alseth <haal@nordicsemi.no>

Author: Rallare

boards/nordic/nrf54l15dk/nrf54l_05_10_15_cpuapp_common.dtsi

@@ -28,7 +28,7 @@
 
 &lfxo {
 	load-capacitors = "internal";
-	load-capacitance-femtofarad = <15500>;
+	load-capacitance-femtofarad = <17000>;
 };
 
 &hfxo {