ffmpeg: enable parallel build

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>

multimedia/ffmpeg/Makefile

@@ -630,7 +630,7 @@ define Build/Configure
 endef
 
 define Build/Compile
-	$(MAKE) -C $(PKG_BUILD_DIR) \
+	$(MAKE) $(PKG_JOBS) -C $(PKG_BUILD_DIR) \
 		DESTDIR="$(PKG_INSTALL_DIR)" \
 		all install
 endef