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/include/linux/ucs2_string.h b/include/linux/ucs2_string.h
new file mode 100644
index 0000000..cbb20af
--- /dev/null
+++ b/include/linux/ucs2_string.h
@@ -0,0 +1,14 @@
+#ifndef _LINUX_UCS2_STRING_H_
+#define _LINUX_UCS2_STRING_H_
+
+#include <linux/types.h>	/* for size_t */
+#include <linux/stddef.h>	/* for NULL */
+
+typedef u16 ucs2_char_t;
+
+unsigned long ucs2_strnlen(const ucs2_char_t *s, size_t maxlength);
+unsigned long ucs2_strlen(const ucs2_char_t *s);
+unsigned long ucs2_strsize(const ucs2_char_t *data, unsigned long maxlength);
+int ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len);
+
+#endif /* _LINUX_UCS2_STRING_H_ */