[Intel-SIG] backport Intel microcode staging feature

[aubreyli]

backport Intel microcode staging feature, there are 7 patches totally.

• 0001-x86-cpu-topology-Make-primary-thread-mask-available-.patch
• 0002-x86-microcode-Introduce-staging-step-to-reduce-late-.patch
• 0003-x86-microcode-intel-Establish-staging-control-logic.patch
• 0004-x86-microcode-intel-Define-staging-state-struct.patch
• 0005-x86-microcode-intel-Implement-staging-handler.patch
• 0006-x86-microcode-intel-Support-mailbox-transfer.patch
• 0007-x86-microcode-intel-Enable-staging-when-available.patch

Patch 0001-x86-cpu-topology-Make-primary-thread-mask-available-.patch heavily depends on CPU toplogy patch series and will be handled after CPU topology patch series merged.

Passed test: # echo 1 > /sys/devices/system/cpu/microcode/reload # dmesg | grep microcode [ 12.090791] microcode: Enabled staging feature. [ 12.098249] microcode: Current revision: 0x800002b0 [ 12.111873] microcode: Microcode Update Driver: v2.2. [ 93.742725] microcode: Staging of patch revision 0x800002f0 succeeded. [ 94.061781] microcode: Updated to revision 0x800002f0, date = 2025-06-04 [ 97.896386] microcode: load: updated on 144 primary CPUs with 0 siblings [ 97.904576] microcode: revision: 0x800002b0 -> 0x800002f0