ACPI: avoid irqrouter_resume might_sleep oops on resume from S4

ACPI: avoid irqrouter_resume might_sleep oops on resume from S4

__might_sleep+0x8e/0x93
acpi_os_wait_semaphore+0x50/0xa3
acpi_ut_acquire_mutex+0x28/0x6a
acpi_ns_get_node+0x46/0x88
acpi_ns_evaluate+0x2d/0xfc
acpi_rs_set_srs_method_data+0xc5/0xe1
acpi_set_current_resources+0x31/0x3f
acpi_pci_link_set+0xfc/0x1a5
irqrouter_resume+0x48/0x5f

and

__might_sleep+0x8e/0x93
kmem_cache_alloc+0x2a/0x8f
acpi_evaluate_integer+0x32/0x96
acpi_bus_get_status+0x30/0x84
acpi_pci_link_set+0x12a/0x1a5
irqrouter_resume+0x48/0x5f

http://bugzilla.kernel.org/show_bug.cgi?id=6810

Signed-off-by: Len Brown <len.brown@intel.com>