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_common.cpp

@@ -31,6 +31,8 @@
  *
  ****************************************************************************/
 
+#include <string.h>
+
 /**
  * @file parameters_common.cpp
  *