switch the modules implementing the block structure to px4_poll such that in posix_sitl simulation the poll works as expected, blocks the module and doesn't overload the CPU

src/modules/local_position_estimator/BlockLocalPositionEstimator.cpp

@@ -221,7 +221,7 @@ void BlockLocalPositionEstimator::update()
 {
 
 	// wait for a sensor update, check for exit condition every 100 ms
-	int ret = poll(_polls, 3, 100);
+	int ret = px4_poll(_polls, 3, 100);
 
 	if (ret < 0) {
 		/* poll error, count it in perf */

src/modules/local_position_estimator/BlockLocalPositionEstimator.hpp

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <px4_posix.h>
 #include <controllib/uorb/blocks.hpp>
 #include <mathlib/mathlib.h>
 #include <systemlib/perf_counter.h>
@@ -262,7 +263,7 @@ private:
 	//BlockDelay<uint64_t, 1, 1, HIST_LEN> _tDelay;
 
 	// misc
-	struct pollfd _polls[3];
+	px4_pollfd_struct_t _polls[3];
 	uint64_t _timeStamp;
 	//uint64_t _time_last_hist;
 	uint64_t _time_last_xy;