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.
