sh: Fix up CPU dependencies for on-chip DMAC.

We only handle SH-3 and SH-4 at present, don't expose it to the
other CPUs.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/drivers/dma/Kconfig

@@ -5,6 +5,7 @@ config SH_DMA_API
 
 config SH_DMA
 	bool "SuperH on-chip DMA controller (DMAC) support"
+	depends on CPU_SH3 || CPU_SH4
 	select SH_DMA_API
 	default n