scatterlist: move the NEED_SG_DMA_LENGTH config symbol to lib/Kconfig

This way we have one central definition of it, and user can select it as
needed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 89c0c72..a36b4e4 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -710,6 +710,7 @@
 	select PCI_MSI
 	select IOMMU_HELPER
 	select IOMMU_SUPPORT
+	select NEED_SG_DMA_LENGTH
 
 	help
 	  Enable PCI support.
@@ -734,9 +735,6 @@
 config HAS_IOMEM
 	def_bool PCI
 
-config NEED_SG_DMA_LENGTH
-	def_bool PCI
-
 config NEED_DMA_MAP_STATE
 	def_bool PCI