fm10k: fix PCI device enable_cnt leak in .io_slot_reset

A previous patch removed the pci_disable_device() call in
.io_error_detected. This call corresponded to a pci_enable_device_mem()
call within .io_slot_reset handler. Change the call here to
a pci_reenable_device() so that it does not increment and leak the
enable_cnt reference count for the device. Without this change, VF
devices may fail during an unbind/bind, and we'll never zero the
reference counter for the pci_dev structure.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>