acpi: Kconfig symbol CONFIG_QFW_ACPI

We have two implementations of write_acpi_tables(). One for writing ACPI
tables based on ACPI_WRITER() entries another based on copying tables from
QEMU.

Create a symbol CONFIG_QFW_ACPI that signifies copying ACPI tables from
QEMU and use it consistently.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index ed7eced..e8e4400 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -540,6 +540,13 @@
 	  Hidden option to enable QEMU fw_cfg interface and uclass. This will
 	  be selected by either CONFIG_CMD_QFW or CONFIG_GENERATE_ACPI_TABLE.
 
+config QFW_ACPI
+	bool
+	default y
+	depends on QFW && GENERATE_ACPI_TABLE && !SANDBOX
+	help
+	  Hidden option to read ACPI tables from QEMU.
+
 config QFW_PIO
 	bool
 	depends on QFW