* config/i386/tm-symmetry.h: Clean up, it is now only used for Dynix.

	* config/i386/tm-symmetry.h:  Clean up, it is now only used for Dynix.
	Remove all conditionals and definitions for ptx.
	I386_REGNO_TO_SYMMETRY moved to here from symm-tdep.c.
	Fix addresses of floating point registers in REGISTER_U_ADDR.
	STORE_STRUCT_RETURN now handles cc and gcc conventions.
	FRAME_CHAIN, FRAMELESS_FUNCTION_INVOCATION, FRAME_SAVED_PC,
	IN_SIGTRAMP, SIGCONTEXT_PC_OFFSET defined to make backtracing through
	signal trampoline code work.
	* config/i386/xm-symmetry.h:  Clean up, it is now only used for Dynix.
	Remove all conditionals and definitions for ptx.
	Remove KDB definitions.