package/oath-toolkit: libpskc needs host-libxml2

When compiling oath-toolkit with PSKC support, with:
BR2_PACKAGE_OATH_TOOLKIT=y
BR2_PACKAGE_OATH_TOOLKIT_PSKC=y

Build is failing on hosts without libxml2, with output:

    make[5]: Entering directory '/buildroot/instance-0/output-1/build/oath-toolkit-2.6.12/libpskc/schemas'
    create -noout \
	    --add "system" "urn:ietf:params:xml:ns:keyprov:pskc" \
		    "/buildroot/instance-0/output-1/build/oath-toolkit-2.6.12/libpskc/schemas/pskc-schema.xsd" \
	    --add "system" "http://www.w3.org/TR/2002/REC-xmldsig-core-20020212/xmldsig-core-schema.xsd" \
		    "/buildroot/instance-0/output-1/build/oath-toolkit-2.6.12/libpskc/schemas/xmldsig-core-schema.xsd" \
	    --add "system" "http://www.w3.org/TR/2002/REC-xmlenc-core-20021210/xenc-schema.xsd" \
		    "/buildroot/instance-0/output-1/build/oath-toolkit-2.6.12/libpskc/schemas/xenc-schema.xsd" \
	    tmp
    /bin/sh: line 1: create: command not found
    make[5]: [Makefile:1267: catalog-pskc.xml] Error 127 (ignored)

The build needs the "xmlcatalog" command, provided the host-libxml2
package. The previous error log does not show the "xmlcatalog" because
it is not found by autoconf, then substituted by an empty string (we
only see its arguments).

This commit fixes the issue by adding this missing dependency.

Fixes:
https://autobuild.buildroot.org/results/d22b8d9ba1f8a948125b4f9713720d070e208799/

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/oath-toolkit/oath-toolkit.mk

@@ -29,7 +29,7 @@ endif
 
 ifeq ($(BR2_PACKAGE_OATH_TOOLKIT_PSKC),y)
 OATH_TOOLKIT_CONF_OPTS += --enable-pskc
-OATH_TOOLKIT_DEPENDENCIES += libxml2
+OATH_TOOLKIT_DEPENDENCIES += host-libxml2 libxml2
 else
 OATH_TOOLKIT_CONF_OPTS += --disable-pskc
 endif