ARM: board: meson: add p200 board

This adds the defconfig and README files for p200 board

Signed-off-by: Mohammad Rasim <mohammad.rasim96@gmail.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/board/amlogic/p200/MAINTAINERS b/board/amlogic/p200/MAINTAINERS
index 77a055b..96fe92d 100644
--- a/board/amlogic/p200/MAINTAINERS
+++ b/board/amlogic/p200/MAINTAINERS
@@ -5,3 +5,4 @@
 F:	board/amlogic/p200/
 F:	configs/nanopi-k2_defconfig
 F:	configs/odroid-c2_defconfig
+F:	configs/p200_defconfig