[POWERPC] IOMMU virtual merge is no longer experimental

Per conversations with BenH, IOMMU virtual merging should no longer
be considered to be an "experimental" feature.  In particular,
CONFIG_VMERGE has been set to "y" in the defconfigs for quite a while.
Signed-off-by: NLinas Vepstas <linas@austin.ibm.com>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

----
 arch/powerpc/Kconfig |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
Signed-off-by: NPaul Mackerras <paulus@samba.org>

arch/powerpc/Kconfig

@@ -181,16 +181,17 @@ config MATH_EMULATION
 	  instructions to run.
 
 config IOMMU_VMERGE
-	bool "Enable IOMMU virtual merging (EXPERIMENTAL)"
-	depends on EXPERIMENTAL && PPC64
-	default n
+	bool "Enable IOMMU virtual merging"
+	depends on PPC64
+	default y
 	help
 	  Cause IO segments sent to a device for DMA to be merged virtually
 	  by the IOMMU when they happen to have been allocated contiguously.
 	  This doesn't add pressure to the IOMMU allocator. However, some
 	  drivers don't support getting large merged segments coming back
-	  from *_map_sg(). Say Y if you know the drivers you are using are
-	  properly handling this case.
+	  from *_map_sg().
+
+	  Most drivers don't have this problem; it is safe to say Y here.
 
 config HOTPLUG_CPU
 	bool "Support for enabling/disabling CPUs"