Add softfpu feature for z80 cpu

git-svn-id: trunk@45747 -

rtl/embedded/system.cfg

@@ -264,3 +264,7 @@
 -SfRANDOM
 -SfRESOURCES
 #endif CPUXTENSA
+
+#ifdef CPUZ80
+-SfSOFTFPU
+#endif CPUZ80