Revert "Makefile: log func name for kamailio flavour"

After commit c3e19d2, the function name is printed by default
unless NO_LOG_FUNC_NAME is defined.
This reverts commit f8584159fa88e92b36f8657d645f00d0ff851099.

Makefile.defs

@@ -704,9 +704,6 @@ endif
 ifeq ($(WITHAS), 1)
 	C_DEFS+= -DWITH_AS_SUPPORT
 endif
-ifeq ($(FLAVOUR),kamailio)
-	C_DEFS+= -DLOG_FUNC_NAME
-endif
 
 ifneq ($(STUN),)
 	C_DEFS+= -DUSE_STUN