imx: imx8mp: Add support for Polyhex Debix Model A SBC

Add support for the Polyhex Debix Model A SBC board.
It is an industrial grade single board computer based on
NXP's i.MX 8M Plus.
Currently supported interfaces are:
- Serial console
- Micro SD
- eQOS and FEC Ethernet

imx8mp-debix-model-a.dts is taken from Linux 6.3.

Signed-off-by: Gilles Talis <gilles.talis@gmail.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
diff --git a/board/polyhex/imx8mp_debix_model_a/MAINTAINERS b/board/polyhex/imx8mp_debix_model_a/MAINTAINERS
new file mode 100644
index 0000000..d3afa91
--- /dev/null
+++ b/board/polyhex/imx8mp_debix_model_a/MAINTAINERS
@@ -0,0 +1,8 @@
+DEBIX MODEL A BOARD (i.MX8M Plus)
+M:	Gilles Talis <gilles.talis@gmail.com>
+S:	Maintained
+F:	arch/arm/dts/imx8mp-debix-model-a.dts
+F:	arch/arm/dts/imx8mp-debix-model-a-u-boot.dtsi
+F:	board/polyhex/imx8mp_debix_model_a/
+F:	include/configs/imx8mp_debix_model_a.h
+F:	configs/imx8mp_debix_model_a_defconfig