exfat: remove 'bps' mount-option

remount fails because exfat_show_options() returns unsupported
option 'bps'.
> # mount -o ro,remount
> exfat: Unknown parameter 'bps'

To fix the problem, just remove 'bps' option from exfat_show_options().

Signed-off-by: Tetsuhiro Kohada <Kohada.Tetsuhiro@dc.MitsubishiElectric.co.jp>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com>