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/ia64/Kconfig b/arch/ia64/Kconfig
index ec2a397..5381e46 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -53,6 +53,7 @@
 	select MODULES_USE_ELF_RELA
 	select ARCH_USE_CMPXCHG_LOCKREF
 	select HAVE_ARCH_AUDITSYSCALL
+	select NEED_SG_DMA_LENGTH
 	default y
 	help
 	  The Itanium Processor Family is Intel's 64-bit successor to
@@ -83,9 +84,6 @@
 config NEED_DMA_MAP_STATE
 	def_bool y
 
-config NEED_SG_DMA_LENGTH
-	def_bool y
-
 config SWIOTLB
        bool