Create tdep->rx_psw_type and tdep->rx_fpsw_type lazily

Create tdep->rx_psw_type and tdep->rx_fpsw_type lazily

I build GDB with all targets enabled, and "set architecture rx",
GDB crashes,

(gdb) set architecture rx

Program received signal SIGSEGV, Segmentation fault.
append_flags_type_flag (type=0x20cc360, bitpos=bitpos@entry=0, name=name@entry=0xd27529 "C") at ../../binutils-gdb/gdb/gdbtypes.c:4926
4926				   name);
(gdb) bt 10
 #0  append_flags_type_flag (type=0x20cc360, bitpos=bitpos@entry=0, name=name@entry=0xd27529 "C") at ../../binutils-gdb/gdb/gdbtypes.c:4926
 #1  0x00000000004ce725 in rx_gdbarch_init (info=..., arches=<optimized out>) at ../../binutils-gdb/gdb/rx-tdep.c:1051
 #2  0x00000000006b05a4 in gdbarch_find_by_info (info=...) at ../../binutils-gdb/gdb/gdbarch.c:5269
 #3  0x000000000060eee4 in gdbarch_update_p (info=...) at ../../binutils-gdb/gdb/arch-utils.c:557
 #4  0x000000000060f8a8 in set_architecture (ignore_args=<optimized out>, from_tty=1, c=<optimized out>) at ../../binutils-gdb/gdb/arch-utils.c:531
 #5  0x0000000000593d0b in do_set_command (arg=<optimized out>, arg@entry=0x20bee81 "rx ", from_tty=from_tty@entry=1, c=c@entry=0x20b1540)
    at ../../binutils-gdb/gdb/cli/cli-setshow.c:455
 #6  0x00000000007665c3 in execute_command (p=<optimized out>, p@entry=0x20bee70 "set architecture rx ", from_tty=1) at ../../binutils-gdb/gdb/top.c:666
 #7  0x00000000006935f4 in command_handler (command=0x20bee70 "set architecture rx ") at ../../binutils-gdb/gdb/event-top.c:577
 #8  0x00000000006938d8 in command_line_handler (rl=<optimized out>) at ../../binutils-gdb/gdb/event-top.c:767
 #9  0x0000000000692c2c in gdb_rl_callback_handler (rl=0x20be7f0 "") at ../../binutils-gdb/gdb/event-top.c:200

The cause is that we want to access some builtin types in gdbarch init, but
it is not initialized yet.  I fix it by creating the type when it is to be
used.  We've already done this in sparc, sparc64 and m68k.

gdb:

2016-12-09  Yao Qi  <yao.qi@linaro.org>

	PR tdep/20954
	* rx-tdep.c (rx_psw_type): New function.
	(rx_fpsw_type): New function.
	(rx_register_type): Call rx_psw_type and rx_fpsw_type.
	(rx_gdbarch_init): Move code to rx_psw_type and
	rx_fpsw_type.

gdb/testsuite:

2016-12-09  Yao Qi  <yao.qi@linaro.org>

	* gdb.base/all-architectures.exp.in: Remove kfail for "rx".