ARM: imx: defconfig: Select CONFIG_FHANDLE

CONFIG_FHANDLE=y is needed when running systemd with version >=210, so that it
can spawn a serial tty via getty.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>