KVM: x86/pmu: Move PMU_CAP_{FW_WRITES,LBR_FMT} into msr-index.h header

KVM: x86/pmu: Move PMU_CAP_{FW_WRITES,LBR_FMT} into msr-index.h header

Move PMU_CAP_{FW_WRITES,LBR_FMT} into msr-index.h and rename them with
PERF_CAP prefix to keep consistent with other perf capabilities macros.

No functional change intended.

Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Tested-by: Xudong Hao <xudong.hao@intel.com>
Link: https://lore.kernel.org/r/20250806195706.1650976-24-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>