patch 8.2.2152: screenpos() does not include the WinBar offset

Problem:    screenpos() does not include the WinBar offset.
Solution:   Use W_WINROW() instead of directly using w_window. (closes #7487)
diff --git a/src/move.c b/src/move.c
index cd90379..69091fd 100644
--- a/src/move.c
+++ b/src/move.c
@@ -1247,7 +1247,7 @@
 	    // character is left or right of the window
 	    row = scol = ccol = ecol = 0;
     }
-    *rowp = wp->w_winrow + row + rowoff;
+    *rowp = W_WINROW(wp) + row + rowoff;
     *scolp = scol + coloff;
     *ccolp = ccol + coloff;
     *ecolp = ecol + coloff;