mtd-utils: mark as nonshared

Since mtd-utils embeds ubi-utils and ubi-utils depends on @NAND_SUPPORT, we
cannot share this package among targets as the SDK processing the package is
not guaranteed to claim NAND_SUPPORT.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

package/utils/mtd-utils/Makefile

@@ -18,6 +18,8 @@ PKG_MIRROR_HASH:=e11b342b85a36b2e438a8412ec52f87621d3046aec1a93039f8c72de9990b2a
 
 PKG_INSTALL:=1
 
+PKG_FLAGS:=nonshared
+
 PKG_BUILD_DEPENDS:=util-linux liblzo zlib
 
 PKG_LICENSE:=GPLv2