PCI: endpoint: Fix double free in __pci_epc_create()

The pci_epc_release() function frees "epc" so the kfree() on the next line
is a double free.  Drop the redundant free.

Fixes: 7711cbb4 ("PCI: endpoint: Fix WARN() when an endpoint driver is removed")
Link: https://lore.kernel.org/r/2ce68694-87a7-4c06-b8a4-9870c891b580@moroto.mountain


Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>