usermod mpu6050: Fix incorrect int type

usermods/mpu6050_imu/mpu6050_imu.cpp

@@ -103,7 +103,7 @@ class MPU6050Driver : public Usermod {
     VectorInt16 aaReal;     // [x, y, z]            gravity-free accel sensor measurements
     VectorInt16 aaWorld;    // [x, y, z]            world-frame accel sensor measurements
     VectorFloat gravity;    // [x, y, z]            gravity vector
-    uint32 sample_count;
+    uint32_t sample_count;
 
     // Usermod output
     um_data_t um_data;