Add si7210 to fmuv3

Author: acfloria

boards/px4/fmu-v3/default.cmake

@@ -41,6 +41,7 @@ px4_add_board(
 		magnetometer # all available magnetometer drivers
 		optical_flow # all available optical flow drivers
 		osd
+		si7210
 		pca9685
 		pca9685_pwm_out
 		#power_monitor/ina226