perf kvm stat: Fix build error

perf kvm stat: Fix build error

Since commit ceea279f9376 ("perf kvm stat: Remove use of the arch
directory"), a native build on Arm64 machine reports:

  util/kvm-stat-arch/kvm-stat-x86.c:7:10: fatal error: asm/svm.h: No such file or directory
    7 | #include <asm/svm.h>
      |          ^~~~~~~~~~~
  compilation terminated.

The build fails to find x86's asm headers when building for Arm64.  Fix
this by including asm headers with relative path instead.

Fixes: ceea279f9376 ("perf kvm stat: Remove use of the arch directory")
Signed-off-by: Leo Yan <leo.yan@arm.com>
Link: https://lore.kernel.org/r/20260206-perf_fix_kvm_stat_error-v1-1-ad40115876be@arm.com
Cc: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: James Clark <james.clark@linaro.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-perf-users@vger.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>