runtime: go fmt runtime2.go

Change-Id: I29a6125c9ef285fc365c4e11ab158b79224ae333
Reviewed-on: https://go-review.googlesource.com/126602
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/runtime/runtime2.go

@@ -842,11 +842,11 @@ var (
 	lfenceBeforeRdtsc    bool
 
 	// Set in runtime.cpuinit.
-	support_erms         bool
-	support_popcnt       bool
-	support_sse2         bool
-	support_sse41        bool
-	arm64_support_atomics      bool
+	support_erms          bool
+	support_popcnt        bool
+	support_sse2          bool
+	support_sse41         bool
+	arm64_support_atomics bool
 
 	goarm                uint8 // set by cmd/link on arm systems
 	framepointer_enabled bool  // set by cmd/link