staging: mt7621-dts: gpio 8 and 9 are vendor specific

There are three pins that can be used for reset gpios.
As mentioned in the application note, there are two
possible way of wiring pcie reset:
* connect gpio19 to all pcie reset pins
* connect gpio19 to pcie0 reset and pick two other
gpios for pcie1 and pcie2

gpio7 and gpio8 may not be used as pcie reset and are
vendor specific. Hence, maintain common mt7621.dtsi with
only gpio19 which is common and make an overlay for gnubee
board which uses all gpio's as resets for pcie. After this
changes release gpios in driver code is not needed anymore.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Link: https://lore.kernel.org/r/20200321072650.7784-2-sergio.paracuellos@gmail.com


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