[ARM] clang-format ARMLowOverheadLoops.cpp (NFC)

I'm going to touch this area in a subsequent patch.

Author: kazutakahirata

llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp

@@ -142,8 +142,8 @@ namespace {
     // Visit all the blocks within the loop, as well as exit blocks and any
     // blocks properly dominating the header.
     void ProcessLoop() {
-      std::function<void(MachineBasicBlock*)> Search = [this, &Search]
-        (MachineBasicBlock *MBB) -> void {
+      std::function<void(MachineBasicBlock *)> Search =
+          [this, &Search](MachineBasicBlock *MBB) -> void {
         if (Visited.count(MBB))
           return;