perf genelf: Fix NO_LIBDW=1 build

perf genelf: Fix NO_LIBDW=1 build

With NO_LIBDW=1 a new unused-parameter warning/error has appeared:
```
util/genelf.c: In function ‘jit_write_elf’:
util/genelf.c:163:32: error: unused parameter ‘load_addr’ [-Werror=unused-parameter]
  163 | jit_write_elf(int fd, uint64_t load_addr, const char *sym,
```

Fixes: e3f612c1d8f3 ("perf genelf: Remove libcrypto dependency and use built-in sha1()")
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20250702175402.761818-1-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>