ARM: dts: imx7-tqma7: add SPI-NOR flash

The SPI-NOR flash on the SoM was missing from the device tree.

The TQMa7 as a designated QSPI_RESET# pin, however depending on the
hardware configuration the pin may be unconnected, or be used for a
different purpose. With this in mind, we mux the pin as a pullup and
define an input hog for it, but keep it a separate pin group, so that it
is easy for dependent Device Trees to modify the configuration.

Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>