NFC: Fix implicit fallthrough by adding a break (and refactoring logic).

Bug: http://b/112564944
Test: Builds same exact binaries.
Change-Id: Iff72144b40c4cd5b6c3ef56fe623b19318d5ef80
diff --git a/rsContext.cpp b/rsContext.cpp
index f69f5ee..e42bacd 100644
--- a/rsContext.cpp
+++ b/rsContext.cpp
@@ -402,15 +402,14 @@
     // The public API will always send NORMAL_GRAPHICS
     // for normal, we adjust here
     case RS_THREAD_PRIORITY_NORMAL_GRAPHICS:
-        if (mIsGraphicsContext) {
-            break;
-        } else {
+        if (!mIsGraphicsContext) {
             if (mHal.flags & RS_CONTEXT_LOW_LATENCY) {
                 p = RS_THREAD_PRIORITY_LOW_LATENCY;
             } else {
                 p = RS_THREAD_PRIORITY_NORMAL;
             }
         }
+        break;
     case RS_THREAD_PRIORITY_LOW:
         break;
     }