sh: Trivial fix for dma-api compile failure.

Trivial fix for arch/sh/drivers/dma/dma-api.c compile failure:

  CC      arch/sh/drivers/dma/dma-api.o
a/arch/sh/drivers/dma/dma-api.c: In function 'dma_wait_for_completion':
a/arch/sh/drivers/dma/dma-api.c:233: error: 'TASK_UNINTERRUPTIBLE' undeclared (first use in this function)
a/arch/sh/drivers/dma/dma-api.c:233: error: (Each undeclared identifier is reported only once
a/arch/sh/drivers/dma/dma-api.c:233: error: for each function it appears in.)
a/arch/sh/drivers/dma/dma-api.c:233: warning: implicit declaration of function 'schedule'

Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>