boards: nxp: mcx_n9xx_evk: unify compat between variants

Harmonize board compats between `mcx_n9xx_evk/mcxn947/cpu0(/qspi)` and
`mcx_n9xx_evk/mcxn947/cpu1` variants.

Signed-off-by: Patryk Koscik <[email protected]>

Author: pkoscik

boards/nxp/mcx_nx4x_evk/mcx_n9xx_evk_mcxn947_cpu0.dtsi

@@ -14,6 +14,7 @@
 #include "mcx_nx4x_evk_cpu0.dtsi"
 
 / {
+	compatible = "nxp,mcxn947", "nxp,mcx";
 	aliases{
 		pwm-0 = &flexpwm1_pwm0;
 	};