KVM: Rename symbols related to enabling virtualization hardware

Rename the various functions (and a variable) that enable virtualization
to prepare for upcoming changes, and to clean up artifacts of KVM's
previous behavior, which required manually juggling locks around
kvm_usage_count.

Drop the "nolock" qualifier from per-CPU functions now that there are no
"nolock" implementations of the "all" variants, i.e. now that calling a
non-nolock function from a nolock function isn't confusing (unlike this
sentence).

Drop "all" from the outer helpers as they no longer manually iterate
over all CPUs, and because it might not be obvious what "all" refers to.

In lieu of the above qualifiers, append "_cpu" to the end of the functions
that are per-CPU helpers for the outer APIs.

Opportunistically prepend "kvm" to all functions to help make it clear
that they are KVM helpers, but mostly because there's no reason not to.

Lastly, use "virtualization" instead of "hardware", because while the
functions do enable virtualization in hardware, there are a _lot_ of
things that KVM enables in hardware.

Defer renaming the arch hooks to future patches, purely to reduce the
amount of churn in a single commit.

Reviewed-by: Chao Gao <chao.gao@intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Acked-by: Kai Huang <kai.huang@intel.com>
Tested-by: Farrah Chen <farrah.chen@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20240830043600.127750-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>