acpi_pci_link_allocate_irq() can return negative gsi even if
entry != NULL. For that case we have a memory leak, so free
entry before returning from acpi_pci_irq_enable() for gsi < 0.
Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org> Cc: All applicable <stable@vger.kernel.org>
[rjw: Subject and changelog] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>