powerpc: Do not redefine NEED_DMA_MAP_STATE

kernel/dma/Kconfig already defines NEED_DMA_MAP_STATE, just select it
from CONFIG_PPC using the same condition as an if guard.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
[mpe: Move it under PPC]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

arch/powerpc/Kconfig

@@ -226,6 +226,7 @@ config PPC
 	select IRQ_DOMAIN
 	select IRQ_FORCED_THREADING
 	select MODULES_USE_ELF_RELA
+	select NEED_DMA_MAP_STATE		if PPC64 || NOT_COHERENT_CACHE
 	select NEED_SG_DMA_LENGTH
 	select NO_BOOTMEM
 	select OF
@@ -885,9 +886,6 @@ config ZONE_DMA
 	bool
 	default y
 
-config NEED_DMA_MAP_STATE
-	def_bool (PPC64 || NOT_COHERENT_CACHE)
-
 config GENERIC_ISA_DMA
 	bool
 	depends on ISA_DMA_API