libbpf: fix ptr to u64 conversion warning on 32-bit platforms

On 32-bit platforms compiler complains about conversion:

libbpf.c: In function ‘perf_event_open_probe’:
libbpf.c:4112:17: error: cast from pointer to integer of different
size [-Werror=pointer-to-int-cast]
  attr.config1 = (uint64_t)(void *)name; /* kprobe_func or uprobe_path */
                 ^
Reported-by: Matt Hart <matthew.hart@linaro.org>
Fixes: b2650027 ("libbpf: add kprobe/uprobe attach API")
Tested-by: Matt Hart <matthew.hart@linaro.org>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/lib/bpf/libbpf.c

@@ -4126,7 +4126,7 @@ static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
 	}
 	attr.size = sizeof(attr);
 	attr.type = type;
-	attr.config1 = (uint64_t)(void *)name; /* kprobe_func or uprobe_path */
+	attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */
 	attr.config2 = offset;		 /* kprobe_addr or probe_offset */
 
 	/* pid filter is meaningful only for uprobes */