[ARM] 4561/1: i.MX/MX1 GPIO parenthes omission and input setup fix

During GPIO testing on PiMX1 board there has been revealed
problem with some pins input functions. The GIUS bit has
to be set for inputs to work reliably too. It is surprising
that input worked on some inputs with incorrect setup before.
DR is not mandatory, but it ensures stable constant level
on internal traces.

Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>