bmon: Fix libncursesw dependency

When libncursesw is available, bmon uses it instead of libncurses.  This
commit adapts the dependencies accordingly.

Signed-off-by: Baptiste Jonglez <bjonglez@illyse.org>

net/bmon/Makefile

@@ -22,7 +22,7 @@ include $(INCLUDE_DIR)/package.mk
 define Package/bmon
   SECTION:=net
   CATEGORY:=Network
-  DEPENDS:=+libncurses +libnl +confuse
+  DEPENDS:=+PACKAGE_libncursesw:libncursesw +!PACKAGE_libncursesw:libncurses +libnl +confuse
   TITLE:=bmon is a portable bandwidth monitor
   URL:=https://github.com/tgraf/bmon/
 endef