mvebu: pcie: Add support for GPIO reset for PCIe device

mvebu: pcie: Add support for GPIO reset for PCIe device

Add support for "marvell,reset-gpio" property to mvebu DW PCIe
driver.
This option is valid when CONFIG_DM_GPIO=y

Change-Id: Ic17c500449050c2fbb700731f1a9ca8b83298986
Signed-off-by: Konstantin Porotchkin <[email protected]>
Signed-off-by: Rabeeh Khoury <[email protected]>
Cc: Stefan Roese <[email protected]>
Cc: Nadav Haklai <[email protected]>
Cc: Neta Zur Hershkovits <[email protected]>
Cc: Igal Liberman <[email protected]>
Cc: Haim Boot <[email protected]>
Signed-off-by: Stefan Roese <[email protected]>