[binutils-gdb] Commonise tdesc_reg and makes use of it in gdbserver tdesc

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT ea3e7d717982e3c467edc7886b1d6cc2807195af ***

Author: Alan Hayward <alan.hayward@arm.com>
Branch: master
Commit: ea3e7d717982e3c467edc7886b1d6cc2807195af

Commonise tdesc_reg and makes use of it in gdbserver tdesc

gdb/
	* Makefile.in: Add arch/tdesc.c
	* common/tdesc.c: New file.
	* common/tdesc.h (tdesc_element_visitor): Move to here.
	(tdesc_element): Likewise.
	(tdesc_reg): Likewise.
	(tdesc_reg_up): Likewise.
	* regformats/regdef.h (reg): Add offset to constructors.
	* target-descriptions.c (tdesc_element_visitor): Move from here.
	(tdesc_element): Likewise.
	(tdesc_reg): Likewise.
	(tdesc_reg_up): Likewise.

gdbserver/
	* Makefile.in: Add common/tdesc.c
	* tdesc.c (init_target_desc): init all reg_defs from register vector.
	(tdesc_create_reg): Create tdesc_reg.
	* tdesc.h (tdesc_feature): Add register vector.