build broken on freebsd due to invalid cast in disk/getFsType()

[knz]

Describe the bug

Build fails:

/github.com/shirou/gopsutil/disk/disk_freebsd.go:195:43: cannot use stat.Fstypename[:] (type []byte) as type []int8 in argument to common.IntToString

To Reproduce

build on FreeBSD

Expected behavior

build succeeds

Environment (please complete the following information):

FreeBSD 13-CURRENT on amd64

Additional context

The following diff fixes the bug and keeps the functionality:

@@ -192,5 +193,5 @@ func parseDevstat(buf []byte) (Devstat, error) {
 }

 func getFsType(stat unix.Statfs_t) string {
-       return common.IntToString(stat.Fstypename[:])
+       return string(stat.Fstypename[:])
 }

[Lomanic]

Upgrade golang.org/x/sys, see #853 for context.