drm/i915/perf: Reverse a ternary to make sparse happy

Avoid

drivers/gpu/drm/i915/i915_perf.c:2442:85: warning: dubious: x | !y

simply by inverting the predicate and reversing the ternary.

v2: Move the long lines into their own function so there is no confusion
on operator precedence.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191101192116.12647-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_perf.c

@@ -2428,6 +2428,13 @@ static int gen8_enable_metric_set(struct i915_perf_stream *stream)
 	return emit_oa_config(stream, oa_config, oa_context(stream));
 }
 
+static u32 oag_report_ctx_switches(const struct i915_perf_stream *stream)
+{
+	return _MASKED_FIELD(GEN12_OAG_OA_DEBUG_DISABLE_CTX_SWITCH_REPORTS,
+			     (stream->sample_flags & SAMPLE_OA_REPORT) ?
+			     0 : GEN12_OAG_OA_DEBUG_DISABLE_CTX_SWITCH_REPORTS);
+}
+
 static int gen12_enable_metric_set(struct i915_perf_stream *stream)
 {
 	struct intel_uncore *uncore = stream->uncore;
@@ -2441,12 +2448,10 @@ static int gen12_enable_metric_set(struct i915_perf_stream *stream)
 			   _MASKED_BIT_ENABLE(GEN12_OAG_OA_DEBUG_DISABLE_CLK_RATIO_REPORTS |
 					      GEN12_OAG_OA_DEBUG_INCLUDE_CLK_RATIO) |
 			   /*
-			    * If the user didn't require OA reports, instruct the
-			    * hardware not to emit ctx switch reports.
+			    * If the user didn't require OA reports, instruct
+			    * the hardware not to emit ctx switch reports.
 			    */
-			   !(stream->sample_flags & SAMPLE_OA_REPORT) ?
-			   _MASKED_BIT_ENABLE(GEN12_OAG_OA_DEBUG_DISABLE_CTX_SWITCH_REPORTS) :
-			   _MASKED_BIT_DISABLE(GEN12_OAG_OA_DEBUG_DISABLE_CTX_SWITCH_REPORTS));
+			   oag_report_ctx_switches(stream));
 
 	intel_uncore_write(uncore, GEN12_OAG_OAGLBCTXCTRL, periodic ?
 			   (GEN12_OAG_OAGLBCTXCTRL_COUNTER_RESUME |