1. move dport access header files to soc 2. reduce dport register write protection. Only protect read operation
1. When dual core cpu run access DPORT register, must do protection. 2. If access DPORT register, must use DPORT_REG_READ/DPORT_REG_WRITE and DPORT_XXX register operation macro.
- fix level 4 interrupt vectors to produce correct backtrace - initialize invalid cache access interrupt on startup - handle invalid cache access in panic handler