ipq806x: fix EA8500 switch control

ipq806x: fix EA8500 switch control

EA8500 has pcie2 slot unequipped.
By EA8500 hw design default pcie2 reset gpio (gpio63) is used to
reset the switch. That's why enabling pcie2 brings the switch into
a working state.

So let's just control the gpio63 without enabling the pcie2 slot.

We have to remove the pcie2_pins node so the gpio63 is not defined
twice. Because pcie2 node has a reference to pcie2_pins we have to
remove it as well.

Signed-off-by: Pavel Kubelun <be.dissent@gmail.com>
[slh: rebase for kernel v4.14 as well]
Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>