advapi32: Use correct function pointer cast

[Andrew Talbot]

Changelog:
    advapi32: Use correct function pointer cast.

diff --git a/dlls/advapi32/advapi.c b/dlls/advapi32/advapi.c
index 96e9d87..1be3a17 100644
--- a/dlls/advapi32/advapi.c
+++ b/dlls/advapi32/advapi.c
@@ -287,7 +287,8 @@ DWORD WINAPI CommandLineFromMsiDescriptor( WCHAR *szDescriptor,
     hmsi = LoadLibraryW( szMsi );
     if (!hmsi)
         return r;
-    mpcfd = (void*) GetProcAddress( hmsi, "MsiProvideComponentFromDescriptorW" );
+    mpcfd = (fnMsiProvideComponentFromDescriptor)GetProcAddress( hmsi,
+                                                                 "MsiProvideComponentFromDescriptorW" );
     if (mpcfd)
         r = mpcfd( szDescriptor, szCommandLine, pcchCommandLine, NULL );
     FreeLibrary( hmsi );