x86/acpi/sleep: Fix compile error when CONFIG_ACPI_SLEEP is not set.

otherwise we get:

arch/x86/built-in.o:(.data+0x5f88): undefined reference to `x86_acpi_suspend_lowlevel'

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: liang tang <liang.tang@oracle.com>
1 file changed