cmake: changes required for qurt build

Fixed CMakeLists.txt to be consistent with module.mk
Converted PX4_TICKS_PER_SEC to define for QURT to get around relocation error
Added stubs for QURT so building a full executable can be tested. This will
enable CI testing without the full Hexagon SDK.

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

src/platforms/qurt/px4_layer/main.cpp

@@ -46,6 +46,7 @@
 #include <string>
 #include <map>
 #include <stdio.h>
+#include <apps.h>
 
 using namespace std;
 
@@ -100,18 +101,17 @@ static void process_commands(map<string,px4_main_t> &apps, const char *cmds)
 	char arg[256];
 
 	// This is added because it is a parameter used by commander, yet created by mavlink.  Since mavlink is not
-        // running on QURT, we need to manually define it so it is available to commander.  "2" is for quadrotor.
+	// running on QURT, we need to manually define it so it is available to commander.  "2" is for quadrotor.
 
-    // Following is hack to prevent duplicate parameter definition error in param parser
-    /**
-     * @board QuRT_App
-     */
+	// Following is hack to prevent duplicate parameter definition error in param parser
+	/**
+	 * @board QuRT_App
+	 */
 	PARAM_DEFINE_INT32(MAV_TYPE,2);
 
 	// Eat leading whitespace
 	eat_whitespace(b, i);
 
-
 	for(;;) {
 		// End of command line
 		if (b[i] == '\n' || b[i] == '\0') {