Change the parameter and return value of write_acpi_tables() to u32
to conform with other table write routines.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

This patch adds the ability to load and link ACPI tables provided by QEMU.
QEMU tells guests how to load and patch ACPI tables through its fw_cfg
interface, by adding a firmware file 'etc/table-loader'. Guests are
supposed to parse this file and execute corresponding QEMU commands.

Signed-off-by: Miao Yan <yanmiaobest@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>

Implement write_acpi_table() to create a minimal working ACPI table.
This includes writing FACS, XSDT, RSDP, FADT, MCFG, MADT, DSDT & SSDT
ACPI table entries.

Use a Kconfig option GENERATE_ACPI_TABLE to tell U-Boot whether we need
actually write the APCI table just like we did for PIRQ routing, MP table
and SFI tables. With ACPI table existence, linux kernel gets control of
power management, thermal management, configuration management and
monitoring in hardware.

Signed-off-by: Saket Sinha <saket.sinha89@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tidied up whitespace and aligned some tabs:
Signed-off-by: Simon Glass <sjg@chromium.org>