sh: Revamp PCI DMA coherence Kconfig bits.

Leaving this configurable caused more trouble than it was ever worth, so
just make it explicit. Boards that are verified one way or the other can
fix up their selects accordingly. We presently default to non-coherent
for most platforms.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 2d3a699..e5ee3b1 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -169,6 +169,12 @@
 config IO_TRAPPED
 	bool
 
+config DMA_COHERENT
+	bool
+
+config DMA_NONCOHERENT
+	def_bool !DMA_COHERENT
+
 source "init/Kconfig"
 
 source "kernel/Kconfig.freezer"
@@ -217,6 +223,7 @@
 
 config CPU_SHX3
 	bool
+	select DMA_COHERENT
 
 config ARCH_SHMOBILE
 	bool