intrapred_neon.c: remove redundant returns

clears some clang-tidy warnings:
https://clang.llvm.org/extra/clang-tidy/checks/readability/redundant-control-flow.html

Change-Id: I821a9152a48ed4200bd6cd7594dcdde24e590ed3
diff --git a/aom_dsp/arm/intrapred_neon.c b/aom_dsp/arm/intrapred_neon.c
index 1df805d..f6348f4 100644
--- a/aom_dsp/arm/intrapred_neon.c
+++ b/aom_dsp/arm/intrapred_neon.c
@@ -1023,7 +1023,6 @@
       break;
     default: break;
   }
-  return;
 }
 
 /* ---------------------P R E D I C T I O N   Z 2--------------------------- */
@@ -1631,7 +1630,6 @@
                                 upsample_above, upsample_left, dx, dy);
       break;
   }
-  return;
 }
 
 /* ---------------------P R E D I C T I O N   Z 3--------------------------- */