Adds Os flag to tinyscheme Makefile

Shaves off about 20KB from tinyscheme binary when doing a mips_24kc
build.

lang/tinyscheme/Makefile

@@ -66,7 +66,7 @@ program.
 endef
 
 define Build/Compile
-	$(call Build/Compile/Default,PLATFORM_FEATURES='-fPIC -DInitFile="\"/usr/lib/tinyscheme/init.scm\""')
+	$(call Build/Compile/Default,PLATFORM_FEATURES='-Os -fPIC -DInitFile="\"/usr/lib/tinyscheme/init.scm\""')
 endef
 
 define Package/tinyscheme/install