Fix AMRWBEnc overflow

Bug: 27898843
Change-Id: Ibb3506bcfc315b5c816892ba65e157db8ea3fdbe
diff --git a/media/libstagefright/codecs/amrwbenc/src/voAMRWBEnc.c b/media/libstagefright/codecs/amrwbenc/src/voAMRWBEnc.c
index 4cafb01..3bdf93a 100644
--- a/media/libstagefright/codecs/amrwbenc/src/voAMRWBEnc.c
+++ b/media/libstagefright/codecs/amrwbenc/src/voAMRWBEnc.c
@@ -1301,10 +1301,10 @@
 
             for (i = 0; i < L_SUBFR; i++)
             {
-                L_tmp = (code2[i] * gain_code)<<1;
-                L_tmp = (L_tmp << 5);
-                L_tmp += (exc2[i] * gain_pit)<<1;
-                L_tmp = (L_tmp << 1);
+                L_tmp = L_mult(code2[i], gain_code);
+                L_tmp = L_shl(L_tmp, 5);
+                L_tmp = L_add(L_tmp, L_mult(exc2[i], gain_pit));
+                L_tmp = L_shl(L_tmp, 1);
                 exc2[i] = voround(L_tmp);
             }