The current implement will cache each ISR vector in ISR vector stack and do
ISR vector stack check when updating PPR. However, there is no need to do this
because:
1) We will not touch vlapic->isrvec_stk[0] except doing vlapic_reset:
So we don't need to do vlapic->isrvec_stk[0] check.
2) We only deliver higher priority interrupt from IRR to ISR:
So we don't need to check whether vlapic->isrvec_stk interrupts is always increasing.
3) There're only 15 different priority interrupt, It will not happened that more that
15 interrupts could been delivered to ISR:
So we don't need to check whether vlapic->isrvec_stk_top will larger than
ISRVEC_STK_SIZE which is 16.
This patch try to remove ISR vector stack and use isrv to cache the vector number for
the highest priority bit that is set in the ISR.
Tracked-On: #1842
Signed-off-by: Li, Fei1 <fei1.li@intel.com>
e793b5d091