efi/libstub: Use %ls for filename

efi_printk can now handle the UTF-16 filename, so print it using efi_err
instead of a separate efi_char16_puts call.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200518190716.751506-23-nivedita@alum.mit.eduSigned-off-by: Ard Biesheuvel <ardb@kernel.org>

drivers/firmware/efi/libstub/file.c

@@ -46,9 +46,7 @@ static efi_status_t efi_open_file(efi_file_protocol_t *volume,
 
 	status = volume->open(volume, &fh, fi->filename, EFI_FILE_MODE_READ, 0);
 	if (status != EFI_SUCCESS) {
-		efi_err("Failed to open file: ");
-		efi_char16_puts(fi->filename);
-		efi_puts("\n");
+		efi_err("Failed to open file: %ls\n", fi->filename);
 		return status;
 	}