configs: stm32746g-eval: Add stm32746g-eval_defconfig

Add stm32746g-eval_defconfig for stm32746g evaluation board to
build U-Boot proper.

Full board description can be found here :
https://www.st.com/en/evaluation-tools/stm32746g-eval.html

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
diff --git a/board/st/stm32f746-disco/MAINTAINERS b/board/st/stm32f746-disco/MAINTAINERS
index 68f61fd..7f128a8 100644
--- a/board/st/stm32f746-disco/MAINTAINERS
+++ b/board/st/stm32f746-disco/MAINTAINERS
@@ -5,5 +5,6 @@
 F:	include/configs/stm32f746-disco.h
 F:	configs/stm32f746-disco_defconfig
 F:	configs/stm32f746-disco_spl_defconfig
+F:	configs/stm32746g-eval_defconfig
 F:	configs/stm32f769-disco_defconfig
 F:	configs/stm32f769-disco_spl_defconfig