* regcache.c (set_register_cached, register_buffer,

	* regcache.c (set_register_cached, register_buffer,
	real_register, pseudo_register fetch_register, store_register):
	New functions.
	(register_changed, read_relative_register_raw_bytes_for_frame,
	registers_changed, registers_fetched, read_register_bytes,
	read_register_gen, write_register_gen, read_register,
	read_signed_register, write_register, supply_register): Replace
	register_valid[] with register_cached() and
	set_register_cached().
	(read_register_bytes, read_register_gen, write_register_gen,
	read_register, read_signed_register, write_register,
	supply_register): Replace registers[] with register_buffer().
	(read_register_bytes, read_register_gen, read_register,
	read_signed_register): Call fetch_register().
	(write_register_gen, write_register): Call real_register() and
	store_register().
	(write_register_bytes): Call store_register().
	* value.h (set_register_cached, register_buffer): Prototype.
	* remote.c (remote_fetch_registers): Allocate regs[] with a
	run-time size.  Replace register_valid[] with
	set_register_cached().
	(store_register_using_P, remote_store_registers): Replace
	registers[] with register_buffer().