[xfsprogs] mkfs: fixup memory leak on exit

[Wilfred Mallawa <wilfred.opensource@gmail.com>]

From: Wilfred Mallawa <wilfred.mallawa@wdc.com>

When running mkfs.xfs with addrsan enabled, the following is reported:

```
==27832==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 9 byte(s) in 1 object(s) allocated from:
    #0 0x7fe6db2e8ac4 in strdup (/lib64/libasan.so.8+0xe8ac4) (BuildId: 5395ec74f54d9ec7bf97c06583dd39a96c230822)
    #1 0x0000004175ce in getstr <blah>/mkfs/xfs_mkfs.c:1767

SUMMARY: AddressSanitizer: 9 byte(s) leaked in 1 allocation(s).
```

Thus, gracefully clean up these string allocation on exit to address the above.

Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
---
 mkfs/xfs_mkfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index 334367b8..fec43987 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -6503,5 +6503,8 @@ main(
 		exit(1);
 
 	libxfs_destroy(&xi);
+	free(cli.xi->data.name);
+	free(cli.xi->log.name);
+	free(cli.xi->rt.name);
 	return 0;
 }
-- 
2.55.0