PCI: mvebu: add support for reset on GPIO

This patch adds a check for DT passed reset-gpios property and deasserts/
asserts reset pin on probe/remove with configurable delay. Corresponding
binding documentation is also updated.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

diff --cc Documentation/devicetree/bindings/pci/mvebu-pci.txt
Simple merge

diff --cc drivers/pci/host/pci-mvebu.c
Simple merge