efi: Add string conversion helper

Signed-off-by: Paul Barker <paul.barker@sancloud.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/include/efi_loader.h b/include/efi_loader.h
index ad01395..8c45e3e 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -1014,9 +1014,10 @@
 /* runtime implementation of memcpy() */
 void efi_memcpy_runtime(void *dest, const void *src, size_t n);
 
-/* commonly used helper function */
+/* commonly used helper functions */
 u16 *efi_create_indexed_name(u16 *buffer, size_t buffer_size, const char *name,
 			     unsigned int index);
+efi_string_t efi_convert_string(const char *str);
 
 extern const struct efi_firmware_management_protocol efi_fmp_fit;
 extern const struct efi_firmware_management_protocol efi_fmp_raw;