x86_64: remove acpi_pci_link_exit()

acpi_pci_link_exit() is both unused and empty.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Len Brown <len.brown@intel.com>

arch/x86/kernel/acpi/sleep_64.c

@@ -115,6 +115,3 @@ static int __init acpi_sleep_setup(char *str)
 
 __setup("acpi_sleep=", acpi_sleep_setup);
 
-void acpi_pci_link_exit(void)
-{
-}