package/mtd: fix zlib build

Commit bb19ffeaab5ba4be0a1033ca326b25d4d4e8203f forgot to move
host-pkgconf dependency from BR2_PACKAGE_MTD_JFFS_UTILS condition to the
new BR2_PACKAGE_ZLIB condition resulting in the following build failure:

hecking for ZLIB... no
configure: error: cannot find zlib

Fixes: bb19ffeaab5ba4be0a1033ca326b25d4d4e8203f
 - http://autobuild.buildroot.org/results/7cbeead738af6302d5f0048a443e3b57d6776bb2

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/mtd/mtd.mk

@@ -28,7 +28,7 @@ MTD_CONF_OPTS += --without-lzo
 endif
 
 ifeq ($(BR2_PACKAGE_ZLIB),y)
-MTD_DEPENDENCIES += zlib
+MTD_DEPENDENCIES += host-pkgconf zlib
 MTD_CONF_OPTS += --with-zlib
 else
 MTD_CONF_OPTS += --without-zlib
@@ -37,7 +37,6 @@ endif
 MTD_CONF_ENV += LDFLAGS="$(MTD_LDFLAGS)"
 
 ifeq ($(BR2_PACKAGE_MTD_JFFS_UTILS),y)
-MTD_DEPENDENCIES += host-pkgconf
 MTD_CONF_OPTS += --with-jffs
 else
 MTD_CONF_OPTS += --without-jffs