cmake: add cpuapp suffix to nRF54L20

common.cmake

@@ -53,6 +53,11 @@ function(nrfxlib_calculate_lib_path lib_path)
       if(DEFINED CONFIG_TRUSTED_EXECUTION_NONSECURE AND ${CALC_LIB_PATH_NS_PROVIDED})
         set(arch_soc_dir ${arch_soc_dir}_ns)
       endif()
+    elseif(DEFINED CONFIG_SOC_NRF54L20_ENGA_CPUAPP)
+      set(arch_soc_dir ${arch_soc_dir}_cpuapp)
+      if(DEFINED CONFIG_TRUSTED_EXECUTION_NONSECURE AND ${CALC_LIB_PATH_NS_PROVIDED})
+        set(arch_soc_dir ${arch_soc_dir}_ns)
+      endif()
     elseif(DEFINED CONFIG_SOC_NRF54H20_CPURAD)
       set(arch_soc_dir ${arch_soc_dir}_cpurad)
     endif()