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/Makefile b/lib/Makefile
index d7946ff..6e2cc56 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -174,3 +174,5 @@
       cmd_build_OID_registry = perl $(srctree)/$(src)/build_OID_registry $< $@
 
 clean-files	+= oid_registry_data.c
+
+obj-$(CONFIG_UCS2_STRING) += ucs2_string.o