KVM: x86: Reorganize code in x86.c to co-locate vCPU blocking/running helpers

Shuffle code around in x86.c so that the various helpers related to vCPU
blocking/running logic are (a) located near each other and (b) ordered so
that HLT emulation can use kvm_vcpu_has_events() in a future path.

No functional change intended.

Link: https://lore.kernel.org/r/20240802195120.325560-5-seanjc@google.com


Signed-off-by: Sean Christopherson <seanjc@google.com>