fec: Use gpio_set_value_cansleep()

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

Based on a patch from Russell King for pci-mvebu.c.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>