Freescale STMP37XX/STMP378X Application UART driver: remove duplicate linux/device.h include

Do not include linux/device.h twice in drivers/tty/serial/mxs-auart.c .
Once is enough.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>