[ARM] 3490/1: i.MX: move uart resources to board files

Patch from Sascha Hauer

This patch moves the i.MX uart resources and the gpio pin setup to the
board files. This allows the boards to decide how many internal uarts
are connected to the outside world and whether they use rts/cts or
not.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>