KVM: PPC: Book3S PR: Fix broken select due to misspelling

Commit 76d837a4 ("KVM: PPC: Book3S PR: Don't include SPAPR TCE code
on non-pseries platforms") added a reference to the globally undefined
symbol PPC_SERIES. Looking at the rest of the commit, PPC_PSERIES was
probably intended.

Change PPC_SERIES to PPC_PSERIES.

Discovered with the
https://github.com/ulfalizer/Kconfiglib/blob/master/examples/list_undefined.py
script.

Fixes: 76d837a4 ("KVM: PPC: Book3S PR: Don't include SPAPR TCE code on non-pseries platforms")
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/kvm/Kconfig

@@ -68,7 +68,7 @@ config KVM_BOOK3S_64
 	select KVM_BOOK3S_64_HANDLER
 	select KVM
 	select KVM_BOOK3S_PR_POSSIBLE if !KVM_BOOK3S_HV_POSSIBLE
-	select SPAPR_TCE_IOMMU if IOMMU_SUPPORT && (PPC_SERIES || PPC_POWERNV)
+	select SPAPR_TCE_IOMMU if IOMMU_SUPPORT && (PPC_PSERIES || PPC_POWERNV)
 	---help---
 	  Support running unmodified book3s_64 and book3s_32 guest kernels
 	  in virtual machines on book3s_64 host processors.