PCI: endpoint: Fix kernel panic after put_device()

'put_device()' calls the relase function 'pci_epf_dev_release()',
which already frees 'epf->name' and 'epf'.

Therefore we must not free them again after 'put_device()'.

Fixes: 5e8cb403 ("PCI: endpoint: Add EP core layer to enable EP controller and EP functions")

Signed-off-by: Rolf Evers-Fischer <rolf.evers.fischer@aptiv.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>