efi: Share struct efi_priv between the app and stub code

At present each of these has its own static variable and helper functions.
Move them into a shared file.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/lib/efi/efi.c b/lib/efi/efi.c
index 69e52e4..cd6bf47 100644
--- a/lib/efi/efi.c
+++ b/lib/efi/efi.c
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0+
 /*
+ * Functions shared by the app and stub
+ *
  * Copyright (c) 2015 Google, Inc
  *
  * EFI information obtained here:
@@ -17,6 +19,33 @@
 #include <efi.h>
 #include <efi_api.h>
 
+static struct efi_priv *global_priv;
+
+struct efi_priv *efi_get_priv(void)
+{
+	return global_priv;
+}
+
+void efi_set_priv(struct efi_priv *priv)
+{
+	global_priv = priv;
+}
+
+struct efi_system_table *efi_get_sys_table(void)
+{
+	return global_priv->sys_table;
+}
+
+struct efi_boot_services *efi_get_boot(void)
+{
+	return global_priv->boot;
+}
+
+unsigned long efi_get_ram_base(void)
+{
+	return global_priv->ram_base;
+}
+
 /*
  * Global declaration of gd.
  *