ti-st: use cpu friendly wait_for_completions

Be nice to CPU and don't hog the resources, use a nice wait_for_interruptible
timeout for completions instead of wait_for_timeout which is
non-interruptible.

Change-Id: I87542c2980978543bc3832f45592b719a61ba5b8
Signed-off-by: Pavan Savoy <pavan_savoy@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>

Conflicts:
	drivers/misc/ti-st/st_kim.c
ti-st: use msleep_interruptible instead of mdelay

Be nice to CPU and use msleep_interruptible instead of msleep which chops the
CPU up into a spin loop.
Used for all delays > 20ms.

Change-Id: I8f84ff34d9191e8fde9af28f81681470571c0b51
Signed-off-by: Pavan Savoy <pavan_savoy@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>