mtd-utils: ensure libmtd.a always gets built

Closes #2785

If only ubi* is selected, libmtd.a wouldn't get built breaking the build.

Based on patch by Patrick Ziegler <patrick.ziegler@fh-kl.de>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

CHANGES

@@ -2,11 +2,13 @@
 
 	Fixes all over the tree.
 
-	Updated/fixed packages: libglib2, module-init-tools, qt
+	Updated/fixed packages: libglib2, module-init-tools,
+	mtd-utils, qt
 
 	Issues resolved (http://bugs.uclibc.org):
 
 	#2479: host-module-init-tools 3.11 fails to build
+	#2785: mtd-utils build fails due to missing libmtd
 	#2809: failed to compile libglib2
 	#2821: [PATCH] Patch for JavaScriptCore in QtWebKit module
 	#2827: qt-4.7.0-pthread_getattr_np.patch invalid for qt 4.6...

package/mtd/mtd.mk

@@ -68,14 +68,12 @@ MTD_MAKE_COMMON_FLAGS = \
 	$(TARGET_CONFIGURE_OPTS) CROSS=$(TARGET_CROSS) \
 	WITHOUT_XATTR=1 WITHOUT_LARGEFILE=1
 
-ifneq ($(MTD_TARGETS_y),)
 define MTD_TARGETS_BUILD
 	$(MAKE1) $(MTD_MAKE_COMMON_FLAGS) \
 		BUILDDIR=$(@D) \
 		-C $(@D) \
-		$(addprefix $(@D)/, $(MTD_TARGETS_y))
+		$(addprefix $(@D)/, lib/libmtd.a $(MTD_TARGETS_y))
 endef
-endif
 
 ifneq ($(MTD_TARGETS_UBI_y),)
 define MTD_TARGETS_UBI_BUILD