gvfs: fix activation of http/dav backend

Since gvfs version 1.2.3, http/dav backend needs libxml2:
https://gitlab.gnome.org/GNOME/gvfs/commit/2ef5b4192f95f9205204215aec33787641608e58

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

package/gvfs/gvfs.mk

@@ -95,8 +95,8 @@ else
 GVFS_CONF_OPTS += --disable-nfs
 endif
 
-ifeq ($(BR2_PACKAGE_LIBSOUP),y)
-GVFS_DEPENDENCIES += libsoup
+ifeq ($(BR2_PACKAGE_LIBSOUP)$(BR2_PACKAGE_LIBXML2),yy)
+GVFS_DEPENDENCIES += libsoup libxml2
 GVFS_CONF_OPTS += --enable-http
 else
 GVFS_CONF_OPTS += --disable-http