mapi32: Cast-qual warning fix

[Andrew Talbot]

Changelog:
    mapi32: Cast-qual warning fix.

diff -urN a/dlls/mapi32/util.c b/dlls/mapi32/util.c
--- a/dlls/mapi32/util.c	2006-05-26 11:35:03.000000000 +0100
+++ b/dlls/mapi32/util.c	2006-09-14 19:23:33.000000000 +0100
@@ -732,7 +732,7 @@
  */
 ULONG WINAPI UlFromSzHex(LPCWSTR lpszHex)
 {
-    LPSTR lpStr = (LPSTR)lpszHex;
+    LPCSTR lpStr = (LPCSTR)lpszHex;
     ULONG ulRet = 0;
 
     TRACE("(%s)\n", debugstr_a(lpStr));