tools perf: Add arm64 sysreg files to MANIFEST

tools perf: Add arm64 sysreg files to MANIFEST

Ian pointed out that source tarballs are incomplete as of commit
e2bdd172e665 ("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: e2bdd172e665 ("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.dev
Signed-off-by: Namhyung Kim <namhyung@kernel.org>