staging: mt7621-pci: use only two phys from device tree

staging: mt7621-pci: use only two phys from device tree

In order to align work with the mt7621-pci-phy part of
the driver and device tree which is now using only two
real phys one of them dual ported properly parse the
device tree and don't call phy initialization for the
slot 1 because is being taking into account when the
phy for the slot 0 is instantiated.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Link: https://lore.kernel.org/r/20200320110123.9907-4-sergio.paracuellos@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>