Staging: rts5208: rtsx_transport.c: Add spaces around -

This patch fixes the following styling issue in rtsx_transport.c
as reported by checkpatch.pl:

CHECK: spaces preferred around that '-' (ctx:VxV)

Signed-off-by: Shaun Ren <shaun.ren@linux.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>