ACPICA: Linux: Add support to exclude <asm/acenv.h> inclusion.

The forthcoming patch will make <acpi/acpi.h> to be visible to all kernel
source code. Thus for the architectures that do not support ACPI and
haven't implemented <asm/acenv.h>, we need to make it excluded.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>