efi_loader: pre-seed UEFI variables

Include a file with the initial values for non-volatile UEFI variables
into the U-Boot binary. If this variable is set, changes to variable PK
will not be allowed.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

include/efi_variable.h

@@ -138,6 +138,14 @@ struct efi_var_file {
  */
 efi_status_t efi_var_to_file(void);
 
+/**
+ * efi_var_restore() - restore EFI variables from buffer
+ *
+ * @buf:	buffer
+ * Return:	status code
+ */
+efi_status_t efi_var_restore(struct efi_var_file *buf);
+
 /**
  * efi_var_from_file() - read variables from file
  *