x86: acpi: Don't touch hardware on HW reduced platforms

If ACPI HW reduced bit in FADT is set we should ignore any ACPI hardware
communications.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NBin Meng <bmeng.cn@gmail.com>

arch/x86/lib/acpi_table.c

@@ -463,6 +463,10 @@ ulong write_acpi_tables(ulong start)
 
 	debug("ACPI: done\n");
 
+	/* Don't touch ACPI hardware on HW reduced platforms */
+	if (fadt->flags & ACPI_FADT_HW_REDUCED_ACPI)
+		return current;
+
 	/*
 	 * Other than waiting for OSPM to request us to switch to ACPI mode,
 	 * do it by ourselves, since SMI will not be triggered.