tools perf: Add arm64 sysreg files to MANIFEST

Ian pointed out that source tarballs are incomplete as of commit
e2bdd172 ("perf build: Generate arm64's sysreg-defs.h and add to
include path"), since the source files needed from the kernel tree do
not appear in the manifest. Add them.
Reported-by: Ian Rogers <irogers@google.com>
Fixes: e2bdd172 ("perf build: Generate arm64's sysreg-defs.h and add to include path")
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20231121192956.919380-2-oliver.upton@linux.devSigned-off-by: Namhyung Kim <namhyung@kernel.org>

tools/perf/MANIFEST

+arch/arm64/tools/gen-sysreg.awk
+arch/arm64/tools/sysreg
 tools/perf
 tools/arch
 tools/scripts