ARM: 5988/1: pgprot_dmacoherent() for non-mmu builds

Commit 26a26d32 ("dma-mapping: switch
ARMv7 DMA mappings to retain 'memory' attribute") added a new macro,
pgprot_dmacoherent(), to correctly map DMA memory. The non-mmu pgtable
support code also needs to implement this macro, otherwise when
compiling you get:

  CC      arch/arm/mm/dma-mapping.o
arch/arm/mm/dma-mapping.c: In function 'dma_alloc_coherent':
arch/arm/mm/dma-mapping.c:320: error: implicit declaration of function 'pgprot_dmacoherent'
arch/arm/mm/dma-mapping.c:320: error: 'pgprot_kernel' undeclared (first use in this function)
arch/arm/mm/dma-mapping.c:320: error: (Each undeclared identifier is reported only once
arch/arm/mm/dma-mapping.c:320: error: for each function it appears in.)
Signed-off-by: NGreg Ungerer <gerg@uclinux.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/include/asm/pgtable-nommu.h

@@ -67,6 +67,7 @@ static inline int pte_file(pte_t pte) { return 0; }
  */
 #define pgprot_noncached(prot)	__pgprot(0)
 #define pgprot_writecombine(prot) __pgprot(0)
+#define pgprot_dmacoherent(prot) __pgprot(0)
 
 
 /*