Delete outdated comment & tidy-up others

Change-Id: I83031180723ee59270ec8fb66b2f73c0796bee25

vp9/common/vp9_prob.h

@@ -39,17 +39,12 @@ typedef int8_t vp9_tree_index;
 
 typedef const vp9_tree_index vp9_tree[];
 
-/* Convert array of token occurrence counts into a table of probabilities
-   for the associated binary encoding tree.  Also writes count of branches
-   taken for each node on the tree; this facilitiates decisions as to
-   probability updates. */
-
 static INLINE vp9_prob clip_prob(int p) {
   return (p > 255) ? 255u : (p < 1) ? 1u : p;
 }
 
 // int64 is not needed for normal frame level calculations.
-// However when outputing entropy stats accumulated over many frames
+// However when outputting entropy stats accumulated over many frames
 // or even clips we can overflow int math.
 #ifdef ENTROPY_STATS
 static INLINE vp9_prob get_prob(int num, int den) {
@@ -65,7 +60,7 @@ static INLINE vp9_prob get_binary_prob(int n0, int n1) {
   return get_prob(n0, n0 + n1);
 }
 
-/* this function assumes prob1 and prob2 are already within [1,255] range */
+/* This function assumes prob1 and prob2 are already within [1,255] range. */
 static INLINE vp9_prob weighted_prob(int prob1, int prob2, int factor) {
   return ROUND_POWER_OF_TWO(prob1 * (256 - factor) + prob2 * factor, 8);
 }