Remove include <log.h> from defines.h

The reason for this is that log.h includes drv_hrt.h which sucks in
half the project's include files with it, which causes strange build
issues

src/lib/parameters/parameters_ioctl.cpp

@@ -38,6 +38,9 @@
  */
 
 #define PARAM_IMPLEMENTATION
+
+#include <errno.h>
+
 #include "param.h"
 #include "parameters_ioctl.h"
 #include <px4_platform_common/defines.h>