Respect per-transfer cs_change field (protocol tweaking support) by
adding and using cs_active/cs_deactive functions.
Signed-off-by: NBryan Wu <bryan.wu@analog.com>
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>