efi: app: Implement %pD in the app

This printf() extension is useful for the app. Add an implementation of
efi_dp_str() so that it works as expected.

Signed-off-by: Simon Glass <sjg@chromium.org>

lib/efi/Kconfig

@@ -11,12 +11,22 @@ config EFI
 
 	  This is used to provide libraries shared by both.
 
+if EFI_LOADER
+
 config EFI_BINARY_EXEC
 	bool "Execute UEFI binary"
 	default y
-	depends on EFI_LOADER
 	help
 	  Select this option if you want to execute the UEFI binary after
 	  loading it with U-Boot load commands or other methods.
 	  You may enable CMD_BOOTEFI_BINARY so that you can use bootefi
 	  command to do that.
+
+config EFI_DEVICE_PATH_TO_TEXT
+	bool "Device path to text protocol"
+	default y
+	help
+	  The device path to text protocol converts device nodes and paths to
+	  human readable strings.
+
+endif # EFI_LOADER

lib/efi_client/efi.c

@@ -196,3 +196,18 @@ void efi_free_pool(void *ptr)
 
 	efi_free(priv, ptr);
 }
+
+/* helper for debug prints.. efi_free_pool() the result. */
+uint16_t *efi_dp_str(struct efi_device_path *dp)
+{
+	struct efi_priv *priv = efi_get_priv();
+	u16 *val;
+
+	if (!priv->efi_dp_to_text)
+		return NULL;
+
+	val = priv->efi_dp_to_text->convert_device_path_to_text(dp, true,
+								true);
+
+	return val;
+}

lib/efi_loader/Kconfig

@@ -356,13 +356,6 @@ endmenu
 
 menu "UEFI protocol support"
 
-config EFI_DEVICE_PATH_TO_TEXT
-	bool "Device path to text protocol"
-	default y
-	help
-	  The device path to text protocol converts device nodes and paths to
-	  human readable strings.
-
 config EFI_DEVICE_PATH_UTIL
 	bool "Device path utilities protocol"
 	default y