efi_loader: Clean up efi_dp_append and efi_dp_concat

Looking back at the initrd storing functionality, we introduced three
functions, efi_dp_append_or_concatenate(), efi_dp_append/concat(). In
hindsight we could have simplified that by a lot. First of all none of
the functions append anything. They all allocate a new device path and
concatenate the contents of two device paths in one. A boolean parameter
controls the final device path -- if that's true an end node is injected
between the two device paths.

So let's rewrite this and make it a bit easier to read. Get rid of
efi_dp_append(), efi_dp_concat() and rename
efi_dp_append_or_concatenate() to efi_dp_concat(). This is far more
intuitive and the only adjustment that is needed is an extra boolean
argument on all callsites.

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

lib/efi_loader/efi_device_path_utilities.c

@@ -76,7 +76,7 @@ static struct efi_device_path * EFIAPI append_device_path(
 	const struct efi_device_path *src2)
 {
 	EFI_ENTRY("%pD, %pD", src1, src2);
-	return EFI_EXIT(efi_dp_append(src1, src2));
+	return EFI_EXIT(efi_dp_concat(src1, src2, false));
 }
 
 /*