MIPS: remove CONFIG_DMA_COHERENT

We can just check for !CONFIG_DMA_NONCOHERENT instead and simplify things
a lot.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19530/
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Tom Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: iommu@lists.linux-foundation.org
Cc: linux-mips@linux-mips.org

arch/mips/include/asm/dma-coherence.h

@@ -21,10 +21,10 @@ enum coherent_io_user_state {
 extern enum coherent_io_user_state coherentio;
 extern int hw_coherentio;
 #else
-#ifdef CONFIG_DMA_COHERENT
-#define coherentio	IO_COHERENCE_ENABLED
-#else
+#ifdef CONFIG_DMA_NONCOHERENT
 #define coherentio	IO_COHERENCE_DISABLED
+#else
+#define coherentio	IO_COHERENCE_ENABLED
 #endif
 #define hw_coherentio	0
 #endif /* CONFIG_DMA_MAYBE_COHERENT */

arch/mips/include/asm/mach-generic/kmalloc.h

@@ -2,8 +2,7 @@
 #ifndef __ASM_MACH_GENERIC_KMALLOC_H
 #define __ASM_MACH_GENERIC_KMALLOC_H
 
-
-#ifndef CONFIG_DMA_COHERENT
+#ifdef CONFIG_DMA_NONCOHERENT
 /*
  * Total overkill for most systems but need as a safe default.
  * Set this one if any device in the system might do non-coherent DMA.