staging: mt7621-pci: change variable to print for slot

We are using the counter to print the slot which has been
enabled. Use the correct associated slot for the port instead.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Link: https://lore.kernel.org/r/20200320110123.9907-5-sergio.paracuellos@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>