Move utf16 functions to kernel core and rename

We want to be able to use the utf16 functions that are currently present
in the EFI variables code in platform-specific code as well. Move them to
the kernel core, and in the process rename them to accurately describe what
they do - they don't handle UTF16, only UCS2.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
diff --git a/lib/Kconfig b/lib/Kconfig
index 3958dc4..fe01d41 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -404,4 +404,7 @@
 	help
 	  Enable fast lookup object identifier registry.
 
+config UCS2_STRING
+        tristate
+
 endmenu