delete matrix submodule

.gitmodules

@@ -14,10 +14,6 @@
 	path = Tools/sitl_gazebo
 	url = https://github.com/PX4/PX4-SITL_gazebo.git
 	branch = master
-[submodule "src/lib/matrix"]
-	path = src/lib/matrix
-	url = https://github.com/PX4/PX4-Matrix.git
-	branch = master
 [submodule "src/drivers/gps/devices"]
 	path = src/drivers/gps/devices
 	url = https://github.com/PX4/PX4-GPSDrivers.git

src/lib/CMakeLists.txt

@@ -31,8 +31,6 @@
 #
 ############################################################################
 
-px4_add_git_submodule(TARGET git_matrix PATH "matrix")
-
 add_subdirectory(airspeed)
 add_subdirectory(avoidance)
 add_subdirectory(battery)

src/lib/matrix

@@ -1 +0,0 @@
-Subproject commit d03bf42f6071f71cbc71bb820a0a4479575e9931