toolchain: fix again stamp file touch

In e6633fd2e37d25f32958f30e852baa216ce1384a I did crap, and added a
quietization inside a shell command, which was already quietized. This
was stupid, and is fixed by this patch.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

toolchain/toolchain-external/ext-tool.mk

@@ -195,4 +195,4 @@ $(STAMP_DIR)/ext-toolchain-installed: $(TOOLCHAIN_EXTERNAL_DEPENDENCIES)
 	if [ -L $${ARCH_SYSROOT_DIR}/lib64 ] ; then \
 		$(call create_lib64_symlinks) ; \
 	fi ; \
-	$(Q)touch $@
+	touch $@