xfs: use strscpy() to instead of strncpy()

xfs: use strscpy() to instead of strncpy()

The implementation of strscpy() is more robust and safer.
That's now the recommended way to copy NUL-terminated strings.

Signed-off-by: Xu Panda <[email protected]>
Signed-off-by: Yang Yang <[email protected]>
Reviewed-by: Darrick J. Wong <[email protected]>
Signed-off-by: Darrick J. Wong <[email protected]>