[clang][CodeGen][AVR] Fix a crash in AVRABIInfo

fixes #131967

Author: benshi001

clang/lib/CodeGen/Targets/AVR.cpp

@@ -135,8 +135,7 @@ class AVRTargetCodeGenInfo : public TargetCodeGenInfo {
     if (GV->isDeclaration())
       return;
     const auto *FD = dyn_cast_or_null<FunctionDecl>(D);
-    if (!FD)
-      return;
+    if (!FD) return;
     auto *Fn = cast<llvm::Function>(GV);
 
     if (FD->getAttr<AVRInterruptAttr>())

clang/test/CodeGen/avr/argument.c

@@ -119,8 +119,8 @@ struct s8_t {
   char a;
 };
 
-// AVR-NOT:  {{.*}} signext
-// TINY-NOT: {{.*}} signext
+// AVR:  define {{.*}} i8 @foob(i8 {{.*}})
+// TINY  define {{.*}} i8 @foob(i8 {{.*}})
 char foob(struct s8_t a) {
   return a.a + 1;
 }