patch 8.2.4043: using int for second argument of ga_init2()

Problem:    Using int for second argument of ga_init2().
Solution:   Remove unnessary type cast (int) when using sizeof().
diff --git a/src/channel.c b/src/channel.c
index 4ab0549..0b8bfb3 100644
--- a/src/channel.c
+++ b/src/channel.c
@@ -2306,7 +2306,7 @@
     garray_T *gap = &chanpart->ch_block_ids;
 
     if (gap->ga_growsize == 0)
-	ga_init2(gap, (int)sizeof(int), 10);
+	ga_init2(gap, sizeof(int), 10);
     if (ga_grow(gap, 1) == OK)
     {
 	((int *)gap->ga_data)[gap->ga_len] = id;