arm64: dts: ti: iot2050: Support IOT2050-SM variant

Main differences between the new variant and Advanced PG2:

1. Arduino interface is removed. Instead, an new ASIC is added for
   communicating with PLC 1200 signal modules.
2. USB 3.0 type A connector is removed, only USB 2.0 type A connector is
   available.
3. DP interface is removed. Instead, to communicate with PLC 1200 signal
   modules, a USB 3.0 type B connector is added but the signals are
   actually not USB.
4. DDR size is increased to 4 GB.
5. Two sensors are added, one tilt sensor and one light sensor.

The light sensor it not yet added to the DT at this stage as it depends
on to-be-added bindings.

Co-developed-by: Chao Zeng <chao.zeng@siemens.com>
Signed-off-by: Chao Zeng <chao.zeng@siemens.com>
Co-developed-by: Li Hua Qian <huaqian.li@siemens.com>
Signed-off-by: Li Hua Qian <huaqian.li@siemens.com>
Signed-off-by: Baocheng Su <baocheng.su@siemens.com>
[Jan: rebase over dtsi refactorings, split-out light sensor, improve LEDs]
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Link: https://lore.kernel.org/r/d24e920547986499f6e8e39c833e414679b12ab4.1707463401.git.jan.kiszka@siemens.com


Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>