cleanup: remove declared variables without any references

2014-02-13  Sanimir Agovic  <sanimir.agovic@intel.com>

	* cris-tdep.c (cris_supply_gregset): Remove zerobuf.
	(_initialize_cris_tdep): Remove cris_set_cmdlist, cris_show_cmdlist.
	* h8300-tdep.c (setmachinelist): Remove global.
	* hppa-tdep.c (hppa_sigtramp): Remove global.
	* mipsnbsd-tdep.c (sigtramp_retcode_mipsel, sigtramp_retcode_mipseb
	RETCODE_NWORDS, RETCODE_SIZE): Wrap code with #if 0.
	* ravenscar-thread.c (update_target_observer): Remove global.
	* rs6000-tdep.c (rs6000_gdbarch_init): Remove segment_regs.