Add FITRIM ioctl to enable discarding unused blocks while mounted.
As current exFAT doesn't have generic ioctl handler, add empty ioctl
function first, and add FITRIM handler.
Signed-off-by: NHyeongseok Kim <hyeongseok@gmail.com>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: NSungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: NNamjae Jeon <namjae.jeon@samsung.com>