kamailio-5.x: update PKG_MAKE_ARGS

kamailio-5.x: update PKG_MAKE_ARGS

- Removes TLS_HOOKS as this is default anyway
- Removes -DUSE_PTHREAD_MUTEX as on supported arches FAST_LOCK is used
  by default, which according to doc/tutorials/locking.txt is fastest.
  -DUSE_PTHREAD_MUTEX will be set by the build system automatically in
  case FAST_LOCK is unsupported, e.g. on ARC.
- Add OpenWrt LDFLAGS via LD_EXTRA_OPTS.
- With OpenWrt LDFLAGS and CPPFLAGS in place there is no need to declare
  PCREDEFS, PCRELIBS nor EXTRA_LIBS. Remove them all.
- With this setup mod-dialplan now links to libpcre as well; add the
  depend accordingly.

Signed-off-by: Sebastian Kemper <sebastian_ml@gmx.net>