MIPS: don't select DMA_MAYBE_COHERENT from DMA_PERDEV_COHERENT

While both option select a form of conditional dma coherence they don't
actually share any code in the implementation, so untangle them.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NPaul Burton <paul.burton@mips.com>

arch/mips/Kconfig

@@ -1111,7 +1111,7 @@ config DMA_MAYBE_COHERENT
 
 config DMA_PERDEV_COHERENT
 	bool
-	select DMA_MAYBE_COHERENT
+	select DMA_NONCOHERENT
 
 config DMA_NONCOHERENT
 	bool

arch/mips/kernel/setup.c

@@ -1067,7 +1067,7 @@ static int __init debugfs_mips(void)
 arch_initcall(debugfs_mips);
 #endif
 
-#if defined(CONFIG_DMA_MAYBE_COHERENT) && !defined(CONFIG_DMA_PERDEV_COHERENT)
+#ifdef CONFIG_DMA_MAYBE_COHERENT
 /* User defined DMA coherency from command line. */
 enum coherent_io_user_state coherentio = IO_COHERENCE_DEFAULT;
 EXPORT_SYMBOL_GPL(coherentio);

arch/mips/mm/c-r4k.c

@@ -1955,22 +1955,21 @@ void r4k_cache_init(void)
 	__flush_icache_user_range	= r4k_flush_icache_user_range;
 	__local_flush_icache_user_range	= local_r4k_flush_icache_user_range;
 
-#if defined(CONFIG_DMA_NONCOHERENT) || defined(CONFIG_DMA_MAYBE_COHERENT)
-# if defined(CONFIG_DMA_PERDEV_COHERENT)
-	if (0) {
-# else
-	if ((coherentio == IO_COHERENCE_ENABLED) ||
-	    ((coherentio == IO_COHERENCE_DEFAULT) && hw_coherentio)) {
-# endif
+#ifdef CONFIG_DMA_NONCOHERENT
+#ifdef CONFIG_DMA_MAYBE_COHERENT
+	if (coherentio == IO_COHERENCE_ENABLED ||
+	    (coherentio == IO_COHERENCE_DEFAULT && hw_coherentio)) {
 		_dma_cache_wback_inv	= (void *)cache_noop;
 		_dma_cache_wback	= (void *)cache_noop;
 		_dma_cache_inv		= (void *)cache_noop;
-	} else {
+	} else
+#endif /* CONFIG_DMA_MAYBE_COHERENT */
+	{
 		_dma_cache_wback_inv	= r4k_dma_cache_wback_inv;
 		_dma_cache_wback	= r4k_dma_cache_wback_inv;
 		_dma_cache_inv		= r4k_dma_cache_inv;
 	}
-#endif
+#endif /* CONFIG_DMA_NONCOHERENT */
 
 	build_clear_page();
 	build_copy_page();