ARM: 6966/1: ep93xx: fix inverted RTS/DTR signals on uart1

ARM: 6966/1: ep93xx: fix inverted RTS/DTR signals on uart1

It was discovered by Roberto Bergo, that RTS/DTR signals are inverted after
the boot, because it was causing him problems with hardware controlled modem
connected on ttyAM0. Todd Valentic came with this patch for the issue.

Discussion: http://tech.groups.yahoo.com/group/ts-7000/message/20259

Comments from Petr Štetiar:

 Sorry, but forget to add Acked-by[1]:

 1. https://patchwork.kernel.org/patch/873052/

Cc: Ryan Mallon <ryan@bluewatersys.com>
Cc: Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Todd Valentic <todd.valentic@sri.com>
Tested-by: Roberto Bergo <roberto.bergo@robson.it>
Signed-off-by: Petr Štetiar <ynezz@true.cz>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>