kernel: Write-strings warnings fix (2 of 2)

[Andrew Talbot]

Changelog:
    kernel: Write-strings warnings fix.

diff -urN a/dlls/kernel/thunk.c b/dlls/kernel/thunk.c
--- a/dlls/kernel/thunk.c	2006-05-23 13:48:03.000000000 +0100
+++ b/dlls/kernel/thunk.c	2006-08-01 19:54:41.000000000 +0100
@@ -323,7 +323,7 @@
 /***********************************************************************
  *           GetThunkStuff    (KERNEL32.53)
  */
-LPVOID WINAPI GetThunkStuff(LPSTR module, LPSTR func)
+LPVOID WINAPI GetThunkStuff(LPCSTR module, LPCSTR func)
 {
     return _loadthunk(module, func, "<kernel>", NULL, 0L);
 }