x86: efi_loader: Ensure the SMBIOS tables are sent via EFI

The EFI-loader code has not been fully converted to use bloblist, so
relies on the SMBIOS-table address being set in global_data.

Set this up in write_tables() so that the SMBIOS tables are actually
available.

Enable the command for x86 QEMU so that the SMBIOS tests actually run.

Signed-off-by: Simon Glass <sjg@chromium.org>
Fixes: 83ce35d6eb ("emulation: Use bloblist to hold tables")
Reported-by: Niklas Sombert <niklas.sombert@uni-duesseldorf.de>

lib/efi_loader/efi_smbios.c

@@ -35,6 +35,7 @@ efi_status_t efi_smbios_register(void)
 	void *buf;
 
 	addr = gd_smbios_start();
+	printf("register %lx\n", addr);
 	if (!addr) {
 		log_err("No SMBIOS tables to install\n");
 		return EFI_NOT_FOUND;