opcodes * rx-dis.c (get_register_name): New function. Provides safe
access to name array.
(get_condition_name, get_flag_name, get_double_register_name)
(get_double_register_high_name, get_double_register_low_name)
(get_double_control_register_name, get_double_condition_name):
Likewise.
(print_insn_rx): Use the accessor functions.