cmake don't build param "c" files and remove param defines

- these aren't actual source code

src/lib/circuit_breaker/circuit_breaker.cpp

@@ -46,12 +46,13 @@
 
 #include <stdint.h>
 #include <px4_platform_common/defines.h>
+#include <lib/parameters/param.h>
 
 bool circuit_breaker_enabled(const char *breaker, int32_t magic)
 {
 	int32_t val = -1;
 
-	return (PX4_PARAM_GET_BYNAME(breaker, &val) == 0) && (val == magic);
+	return (param_get(param_find(breaker), &val) == 0) && (val == magic);
 }
 
 bool circuit_breaker_enabled_by_val(int32_t breaker_val, int32_t magic)

src/lib/parameters/param.h

@@ -410,27 +410,6 @@ __EXPORT void	param_print_status(void);
  */
 __EXPORT void	param_control_autosave(bool enable);
 
-/*
- * Macros creating static parameter definitions.
- *
- * Note that these structures are not known by name; they are
- * collected into a section that is iterated by the parameter
- * code.
- *
- * Note that these macros cannot be used in C++ code due to
- * their use of designated initializers.  They should probably
- * be refactored to avoid the use of a union for param_value_u.
- */
-
-/** define an int32 parameter */
-#define PARAM_DEFINE_INT32(_name, _default)
-
-/** define a float parameter */
-#define PARAM_DEFINE_FLOAT(_name, _default)
-
-/** define a parameter that points to a structure */
-#define PARAM_DEFINE_STRUCT(_name, _default)
-
 /**
  * Parameter value union.
  */