Use the new CPUModel enum names from libpeci

libpeci was updated with new CPUModel names, so update uses here to
match.

Change-Id: I5dddd285ae6bd90f9158ca8e8ff6e2b589ee25ce
Signed-off-by: Jason M. Bills <jason.m.bills@intel.com>
diff --git a/src/peci_pcie.cpp b/src/peci_pcie.cpp
index 4199045..50ef3e2 100644
--- a/src/peci_pcie.cpp
+++ b/src/peci_pcie.cpp
@@ -112,7 +112,7 @@
 
         switch (model)
         {
-            case skx:
+            case skylake:
             {
                 // Get the assigned CPU bus numbers from CPUBUSNO and CPUBUSNO1
                 // (B(0) D8 F2 offsets CCh and D0h)