package/libmng: fix optional dependency to lcms2

"0ce9b533e3 libmng: new package" introduced a typo that makes the
optional dependency to lcms2 ineffective.

Fix the typo LIBMNG_DEPDENDENCIES -> LIBMNG_DEPENDENCIES.

Signed-off-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libmng/libmng.mk

@@ -14,7 +14,7 @@ LIBMNG_LICENSE = libmng license
 LIBMNG_LICENSE_FILES = LICENSE
 
 ifeq ($(BR2_PACKAGE_LCMS2),y)
-LIBMNG_DEPDENDENCIES += lcms2
+LIBMNG_DEPENDENCIES += lcms2
 else
 LIBMNG_CONF_OPTS += --without-lcms2
 endif