Convert the RX target to make use of target descriptions.

Convert the RX target to make use of target descriptions.

gdb/ChangeLog

2019-08-25  Yoshinori Sato <ysato@users.sourceforge.jp>

	* gdb/rx-tdep.c (rx_register_names): New.
	(rx_register_name): Delete.
	(rx_psw_type): Delete.
	(rx_fpsw_type): Delete.
	(rx_register_type): Delete.
	(rx_gdbarch_init): Convert target-descriptions.
	(_initialize_rx_tdep): Add initialize_tdesc_rx.
	* gdb/features/Makefile: Add rx.xml.
	* gdb/features/rx.xml: New.
	* gdb/features/rx.c: Generated.
	* gdb/NEWS: Mention target description support.

gdb/doc/ChangeLog:

2019-08-25  Yoshinori Sato <ysato@users.sourceforge.jp>

	* gdb.texinfo (Standard Target Features): Add RX Features sub-section.