gdbarch software_single_step frame_info to regcache: sparc

gdb:

2016-11-22  Yao Qi  <yao.qi@linaro.org>

	* sparc-tdep.c (sparc_analyze_control_transfer): Replace parameter
	frame with regcache.  Call get_current_frame.
	(sparc_software_single_step): Call get_regcache_arch instead of
	get_frame_arch.  Call regcache_raw_get_unsigned instead of
	get_frame_register_unsigned.