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: 83ce35d6ebb ("emulation: Use bloblist to hold tables")
Reported-by: Niklas Sombert <niklas.sombert@uni-duesseldorf.de>
Tested-by: Niklas Sombert <niklas.sombert@uni-duesseldorf.de>
Tested-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/arch/x86/lib/tables.c b/arch/x86/lib/tables.c
index ec52992..d7f183f 100644
--- a/arch/x86/lib/tables.c
+++ b/arch/x86/lib/tables.c
@@ -126,6 +126,8 @@
 			use_high = true;
 			if (!gd->arch.table_start_high)
 				gd->arch.table_start_high = rom_addr;
+			if (table->tag == BLOBLISTT_SMBIOS_TABLES)
+				gd_set_smbios_start(rom_addr);
 		}
 		rom_table_end = table->write(rom_addr);
 		if (!rom_table_end) {