package/mender-update-modules: ipk support depends on MMU, wchar

Since its inclusion in commit [1], the
BR2_PACKAGE_MENDER_UPDATE_MODULES_IPK config selects
BR2_PACKAGE_OPKG without propagating its dependencies on MMU and
wchar.

This commit fixes this issue.

Fixes:

    WARNING: unmet direct dependencies detected for BR2_PACKAGE_OPKG
      Depends on [n]: BR2_USE_MMU [=y] && BR2_USE_WCHAR [=n]
      Selected by [y]:
      - BR2_PACKAGE_MENDER_UPDATE_MODULES_IPK [=y] && BR2_PACKAGE_MENDER_UPDATE_MODULES [=y]

[1] https://gitlab.com/buildroot.org/buildroot/-/commit/a474642fdcd8c69e12126bbe8304479aa855d916

Cc: Adam Duskett <adam.duskett@amarulasolutions.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/mender-update-modules/Config.in

@@ -108,6 +108,8 @@ comment "docker support needs a glibc or musl toolchain w/ threads, headers >= 3
 
 config BR2_PACKAGE_MENDER_UPDATE_MODULES_IPK
 	bool "ipk"
+	depends on BR2_USE_MMU # opkg
+	depends on BR2_USE_WCHAR # opkg -> libarchive
 	select BR2_PACKAGE_OPKG
 	help
 	  The IPK Update Module allows opkg-based packages to be
@@ -118,6 +120,10 @@ config BR2_PACKAGE_MENDER_UPDATE_MODULES_IPK
 
 	  https://github.com/mendersoftware/mender-update-modules/tree/master/ipk
 
+comment "ipk support needs a toolchain w/ wchar"
+	depends on BR2_USE_MMU
+	depends on !BR2_USE_WCHAR
+
 config BR2_PACKAGE_MENDER_UPDATE_MODULES_PODMAN
 	bool "podman"
 	depends on BR2_USE_MMU  # podman