ACPI / PCI: fix acpi_pci_irq_enable() memory leak

In acpi_pci_irq_enable(), 'entry' is allocated by kzalloc() in
acpi_pci_irq_check_entry() (invoked from acpi_pci_irq_lookup()). However,
it is not deallocated if acpi_pci_irq_valid() returns false, leading to a
memory leak. To fix this issue, free 'entry' before returning 0.

Fixes: e237a551 ("x86/ACPI/PCI: Recognize that Interrupt Line 255 means "not connected"")
Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>