ARM: dts: add gpio-ranges property to iMX GPIO controllers

To establish a connection between GPIO controllers and pin multiplexor
controller add gpio-ranges properties to all GPIO controllers found
on iMX50, iMX6Q/D, iMX6DL/S, iMX6SL, iMX6SX, iMX6UL and iMX7D/S
SoCs. The change was done after human parsing of output from

% gawk -n '{ sub(/.*__/, ""); if ($1 ~ "^GPIO") print $1, $2/4}' imxXX-pinfunc.h | sort -n

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>