sandbox: Allow building with GENERATE_ACPI_TABLE

At present this option is missing a header file, a function prototype and
the qfw driver needs a header included.

Fix these problems so we can enable this option on sandbox. This will
increase the build coverage.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/include/asm/acpi_table.h b/arch/sandbox/include/asm/acpi_table.h
index 921c7f4..ae17f6c 100644
--- a/arch/sandbox/include/asm/acpi_table.h
+++ b/arch/sandbox/include/asm/acpi_table.h
@@ -6,4 +6,6 @@
 #ifndef __ASM_ACPI_TABLE_H__
 #define __ASM_ACPI_TABLE_H__
 
+ulong write_acpi_tables(ulong start);
+
 #endif /* __ASM_ACPI_TABLE_H__ */
diff --git a/arch/sandbox/include/asm/tables.h b/arch/sandbox/include/asm/tables.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/arch/sandbox/include/asm/tables.h
diff --git a/drivers/misc/qfw.c b/drivers/misc/qfw.c
index ea00be8..a298e5c 100644
--- a/drivers/misc/qfw.c
+++ b/drivers/misc/qfw.c
@@ -14,6 +14,7 @@
 #include <qfw.h>
 #include <dm.h>
 #include <misc.h>
+#include <tables_csum.h>
 #ifdef CONFIG_GENERATE_ACPI_TABLE
 #include <asm/tables.h>
 #endif