[IA64] Enable SWIOTLB only when needed

Don't force CONFIG_SWIOTLB on when not actually needed (i.e. HP_ZX1 and
SGI_SN2).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/Kconfig

@@ -30,7 +30,6 @@ config MMU
 
 config SWIOTLB
        bool
-       default y
 
 config RWSEM_XCHGADD_ALGORITHM
 	bool
@@ -88,6 +87,7 @@ config IA64_GENERIC
 	bool "generic"
 	select NUMA
 	select ACPI_NUMA
+	select SWIOTLB
 	help
 	  This selects the system type of your hardware.  A "generic" kernel
 	  will run on any supported IA-64 system.  However, if you configure
@@ -104,6 +104,7 @@ config IA64_GENERIC
 
 config IA64_DIG
 	bool "DIG-compliant"
+	select SWIOTLB
 
 config IA64_HP_ZX1
 	bool "HP-zx1/sx1000"
@@ -113,6 +114,7 @@ config IA64_HP_ZX1
 
 config IA64_HP_ZX1_SWIOTLB
 	bool "HP-zx1/sx1000 with software I/O TLB"
+	select SWIOTLB
 	help
 	  Build a kernel that runs on HP zx1 and sx1000 systems even when they
 	  have broken PCI devices which cannot DMA to full 32 bits.  Apart
@@ -131,6 +133,7 @@ config IA64_SGI_SN2
 
 config IA64_HP_SIM
 	bool "Ski-simulator"
+	select SWIOTLB
 
 endchoice