av1_compute_qdelta_by_rate: normalize function params

this fixes a warning under Visual Studio:
av1\encoder\ratectrl.c(2235): warning C4028: formal parameter 1
different from declaration

Change-Id: I319e67c0bb8edd9ae845cdc69c281d6efa1a5998

av1/encoder/ratectrl.c

diff --git a/av1/encoder/ratectrl.c b/av1/encoder/ratectrl.c
index 706e4ff..85e7d79 100644
--- a/av1/encoder/ratectrl.c
+++ b/av1/encoder/ratectrl.c
@@ -2234,7 +2234,7 @@
   return low;
 }
 
-int av1_compute_qdelta_by_rate(const AV1_COMP *const cpi, FRAME_TYPE frame_type,
+int av1_compute_qdelta_by_rate(const AV1_COMP *cpi, FRAME_TYPE frame_type,
                                int qindex, double rate_target_ratio) {
   const RATE_CONTROL *rc = &cpi->rc;