with other functionalities removed.
reason:
by doing this we can reduce context switch time,
When we exit from an interrupt handler, we directly use tcb->xcp.regs
before
text data bss dec hex filename
138805 337 24256 163398 27e46 nuttx
after
text data bss dec hex filename
138499 337 24240 163076 27d04 nuttx
szie change -322
Signed-off-by: hujun5 <hujun5@xiaomi.com>
c5ecc49c10