target/tricore: Remove unused fields from CPUTriCoreState

target/tricore: Remove unused fields from CPUTriCoreState

Remove dead code:
- unused fields in CPUTriCoreState
- (unexisting) tricore_def_t structure
- forward declaration of tricore_boot_info structure
  (declared in "hw/tricore/tricore.h", used once in
   hw/tricore/tricore_testboard.c).

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Message-Id: <20230117184217.83305-1-philmd@linaro.org>