board: phytec: MAINTAINERS: add missing phytec doc files

Add rst documentation files to the respective MAINTAINERS file for
PHYTEC boards.

Signed-off-by: Yannic Moog <y.moog@phytec.de>
Reviewed-by: Teresa Remmet <t.remmet@phytec.de>
diff --git a/board/phytec/phycore_imx8mm/MAINTAINERS b/board/phytec/phycore_imx8mm/MAINTAINERS
index cf6f92c..e46e369 100644
--- a/board/phytec/phycore_imx8mm/MAINTAINERS
+++ b/board/phytec/phycore_imx8mm/MAINTAINERS
@@ -12,4 +12,5 @@
 F:      configs/phycore-imx8mm_defconfig
 F:	doc/board/phytec/imx8mm-phygate-tauri-l.rst
 F:	doc/board/phytec/index.rst
+F:	doc/board/phytec/phycore_imx8mm.rst
 F:      include/configs/phycore_imx8mm.h
diff --git a/board/phytec/phycore_imx8mp/MAINTAINERS b/board/phytec/phycore_imx8mp/MAINTAINERS
index cb7ce55..d3beb97 100644
--- a/board/phytec/phycore_imx8mp/MAINTAINERS
+++ b/board/phytec/phycore_imx8mp/MAINTAINERS
@@ -6,4 +6,5 @@
 F:      arch/arm/dts/imx8mp-phyboard-pollux-rdk-u-boot.dtsi
 F:      board/phytec/phycore_imx8mp/
 F:      configs/phycore-imx8mp_defconfig
+F:	doc/board/phytec/phycore-imx8mp.rst
 F:      include/configs/phycore_imx8mp.h