feat: overall implementation of vector irq
This patch generalize the irq handling on up/mp system by adding the
`rt_hw_irq_exit()` & `rt_hw_vector_irq_sched()` API.
Changes:
- Added `rt_hw_irq_exit()` and `rt_hw_vector_irq_sched()` APIs for unified IRQ management.
- Refactored assembly code for both UP and MP systems to use the new IRQ handling flow.
- Removed redundant code and optimized exception handling paths.
Signed-off-by: Shell <smokewood@qq.com>
fd496e4cc4