comctl32: Constify some variables (3 of 12)

[Andrew Talbot]

Changelog:
    comctl32: Constify some variables.

diff -urN a/dlls/comctl32/commctrl.c b/dlls/comctl32/commctrl.c
--- a/dlls/comctl32/commctrl.c	2007-03-23 14:23:40.000000000 +0000
+++ b/dlls/comctl32/commctrl.c	2007-03-31 14:47:35.000000000 +0100
@@ -1490,7 +1490,7 @@
     return FALSE;
 }
 
-static int CALLBACK PathWordBreakProc(LPWSTR lpch, int ichCurrent, int cch, int code)
+static int CALLBACK PathWordBreakProc(LPCWSTR lpch, int ichCurrent, int cch, int code)
 {
     if (code == WB_ISDELIMITER)
         return IsDelimiter(lpch[ichCurrent]);