lib: fix selection of CONFIG_CHARSET

lib/charset.c is not optional for
EFI_APP || EFI_LOADER || UFS || UT_UNICODE.
These must select CONFIG_CHARSET.

Fixes: 726cd9836db0 ("efi: Make unicode printf available to the app")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/test/Kconfig b/test/Kconfig
index e15ba23..7f3447a 100644
--- a/test/Kconfig
+++ b/test/Kconfig
@@ -91,6 +91,7 @@
 	bool "Unit tests for Unicode functions"
 	depends on UNIT_TEST
 	default y
+	select CHARSET
 	help
 	  Enables the 'ut unicode' command which tests that the functions for
 	  manipulating Unicode strings work correctly.