tools: PCI: Fix fd leakage

tools: PCI: Fix fd leakage

BugLink: https://bugs.launchpad.net/bugs/1862227
commit 3c379a59b4795d7279d38c623e74b9790345a32b upstream.

We should close fd before the return of run_test.

Fixes: 3f2ed8134834 ("tools: PCI: Add a userspace tool to test PCI endpoint")
Signed-off-by: Hewenliang <hewenliang4@huawei.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>