x86: Use PentiumPro-optimized partial_csum() on VIA C7

Testing on the OLPC XO-1.5 (VIA C7-M 1000MHz CPU) shows a partial_csum()
speed increase by a factor of 1.5 when we switch to the Pentium-optimized
version.
Signed-off-by: NDaniel Drake <dsd@laptop.org>
Cc: dilinger@queued.net
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/Kconfig.cpu

@@ -371,7 +371,7 @@ config X86_INTEL_USERCOPY
 
 config X86_USE_PPRO_CHECKSUM
 	def_bool y
-	depends on MWINCHIP3D || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MEFFICEON || MGEODE_LX || MCORE2 || MATOM
+	depends on MWINCHIP3D || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MVIAC7 || MEFFICEON || MGEODE_LX || MCORE2 || MATOM
 
 config X86_USE_3DNOW
 	def_bool y