ARM i.MX53: add dts for the TQ tqma53 module

The tqma53 is an embedded module that has some features on board (e.g. emmc),
but mostly just provides access to them on its interface.
Going along with the imx53.dtsi, the tqma53.dtsi specifies the existing
devices and their pinctrl for this module. All devices that are not on the
module are disabled by default and need to be enabled in a baseboard DT.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>