perf/x86/intel: Remove redundant test from intel_pmu_lbr_add()

By the time we call pmu::add(), event->ctx must be set, and we
even already rely on this, so remove that test from
intel_pmu_lbr_add().
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

arch/x86/events/intel/lbr.c

@@ -440,8 +440,7 @@ void intel_pmu_lbr_add(struct perf_event *event)
 	}
 	cpuc->br_sel = event->hw.branch_reg.reg;
 
-	if (branch_user_callstack(cpuc->br_sel) && event->ctx &&
-					event->ctx->task_ctx_data) {
+	if (branch_user_callstack(cpuc->br_sel) && event->ctx->task_ctx_data) {
 		task_ctx = event->ctx->task_ctx_data;
 		task_ctx->lbr_callstack_users++;
 	}