[SYCL][NFC] Code cleanup revealed by self-build.

Remove redundant false case in switch statement following:
https://llvm.org/docs/CodingStandards.html#don-t-use-default-labels-in-fully-covered-switches-over-enumerations

Author: zahiraam

clang/lib/Sema/SemaSYCL.cpp

@@ -3481,8 +3481,8 @@ static const char *paramKind2Str(KernelParamKind K) {
     CASE(std_layout);
     CASE(sampler);
     CASE(pointer);
-    return "<ERROR>";
   }
+    return "<ERROR>";
 #undef CASE
 }