POSIX: Fixes for ARMv7 build

uint64_t needs to use PRIu64 in printf.
Clang-3.5 found an error is variable types for a compare.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

src/platforms/posix/drivers/airspeedsim/airspeedsim.cpp

@@ -211,7 +211,7 @@ Airspeed::ioctl(device::file_t *filp, int cmd, unsigned long arg)
 					bool want_start = (_measure_ticks == 0);
 
 					/* convert hz to tick interval via microseconds */
-					long ticks = USEC2TICK(1000000 / arg);
+					unsigned long ticks = USEC2TICK(1000000 / arg);
 
 					/* check against maximum rate */
 					if (ticks < USEC2TICK(_conversion_interval))

src/platforms/posix/px4_layer/drv_hrt.c

@@ -42,6 +42,7 @@
 #include <semaphore.h>
 #include <time.h>
 #include <string.h>
+#include <inttypes.h>
 #include "hrt_work.h"
 
 static struct sq_queue_s	callout_queue;
@@ -301,7 +302,7 @@ hrt_call_internal(struct hrt_call *entry, hrt_abstime deadline, hrt_abstime inte
 		sq_rem(&entry->link, &callout_queue);
 
 	if (interval < HRT_INTERVAL_MIN) {
-		PX4_ERR("hrt_call_internal interval too short: %lu", interval);
+		PX4_ERR("hrt_call_internal interval too short: %" PRIu64, interval);
 	}
 	entry->deadline = deadline;
 	entry->period = interval;