Add cpu detection support for comet lake U

Comet Lake U CPUs have family: 6, model: 6, extended family: 0, and
extended model: 10 were not being correctly detected by GETARCH during
openblas builds and would show CORE=UNKNOWN and LIBCORE=unknown. This
commit adds the necessary information to cpuid_x86 to detect extended
family 10 model 6 and return the proper core information. It's
essentially just a skylake cpu, not skylake x, so I just took the used
the same return fields as skylake.

cpuid_x86.c

@@ -1955,6 +1955,19 @@ int get_coretype(void){
 	    return CORE_NEHALEM;
         }
         break;
+      case 10:
+        switch (model) {
+    case 6:
+      // Comet Lake U
+            if(support_avx())
+  #ifndef NO_AVX2
+              return CORE_HASWELL;
+  #else
+          return CORE_SANDYBRIDGE;
+  #endif
+            else
+          return CORE_NEHALEM;
+        }
       case 5:
         switch (model) {
 	case 6: