Stop remote_read_bytes from handling partial reads itself.

	Stop remote_read_bytes from handling partial reads itself.

	* remote-fileio.c: Include target.h.
	(remote_fileio_write_bytes): Delete.
	(remote_fileio_func_open, remote_fileio_func_write)
	(remote_fileio_func_rename, remote_fileio_func_unlink): Use
	target_read_memory.
	(remote_fileio_func_stat): Use target_read_memory and
	target_write_memory.
	(remote_fileio_func_gettimeofday): Use target_write_memory.
	(remote_fileio_func_system): Use target_read_memory.
	* remote.c (remote_write_bytes): Make it static.
	(remote_read_bytes): Don't handle partial reads here.
	* remote.h (remote_read_bytes): Delete declaration.