AVRExpandPseudoInsts.cpp: Fix a warning. [-Wunused-but-set-variable]

It has been enabled since llvmorg-15-init-5683-g2af845a6519c, aka D122271.

Author: chapuni

llvm/lib/Target/AVR/AVRExpandPseudoInsts.cpp

@@ -141,6 +141,7 @@ bool AVRExpandPseudo::runOnMachineFunction(MachineFunction &MF) {
     // Continue expanding the block until all pseudos are expanded.
     do {
       assert(ExpandCount < 10 && "pseudo expand limit reached");
+      (void)ExpandCount;
 
       bool BlockModified = expandMBB(MBB);
       Modified |= BlockModified;