sdl_mixer: fix sdl dependency

package/sdl_mixer/Config.in

@@ -1,8 +1,8 @@
 config BR2_PACKAGE_SDL_MIXER
 	bool "SDL_mixer"
 	default n
+	depends on BR2_PACKAGE_SDL
 	help
-
 	  SDL_mixer is a sample multi-channel audio mixer library.
 	  It supports any number of simultaneously playing channels of
 	  16 bit stereo audio, plus a single channel of music, mixed

package/sdl_mixer/sdl_mixer.mk

@@ -48,7 +48,7 @@ $(TARGET_DIR)/usr/lib/libSDL_mixer.so: $(STAGING_DIR)/usr/lib/libSDL_mixer.so
 	cp -dpf $(STAGING_DIR)/usr/lib/libSDL_mixer*.so* $(TARGET_DIR)/usr/lib/
 	-$(STRIPCMD) $(STRIP_STRIP_UNNEEDED) $(TARGET_DIR)/usr/lib/libSDL_mixer*.so*
 
-sdl_mixer: uclibc $(TARGET_DIR)/usr/lib/libSDL_mixer.so
+sdl_mixer: sdl uclibc $(TARGET_DIR)/usr/lib/libSDL_mixer.so
 
 sdl_mixer-clean:
 	rm -f $(TARGET_DIR)/usr/lib/libSDL_mixer*.so*