Fix out-of-bounds access in IT66021_Get_VTMG() bubble sort

The inner loop in IT66021_Get_VTMG() reads r9a[j+1] while iterating j from
IT66121_9A_READ_N - 1, which can access one element past the end of the array.

This change adjusts the loop bound to prevent out-of-bounds access while
preserving the existing sorting behavior.

Is a full refactor necessary to address the bounds violation?

Author: Strykar

src/driver/it66021.c

@@ -232,7 +232,7 @@ int IT66021_Get_VTMG(int *freq_ref) {
     }
 
     for (i = 0; i < IT66121_9A_READ_N; i++) {
-        for (j = IT66121_9A_READ_N - 1; j >= i; j--) {
+        for (j = IT66121_9A_READ_N - 2; j >= i; j--) {
             if (r9a[j] > r9a[j + 1]) {
                 int temp = r9a[j];
                 r9a[j] = r9a[j + 1];