We are in a context where we can sleep, and the PCIe reset gpio may be on
an I2C expander.  Use the cansleep() variant when setting the GPIO value.

Tested-by: Willy Tarreau <w@1wt.eu> (Iomega iConnect Kirkwood, MiraBox Armada 370)
Tested-by: Andrew Lunn <andrew@lunn.ch> (D-Link DIR664 Kirkwood)
Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> (Armada XP GP)
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>