get_display_dc() may be locking display_dc_section at the end of
user driver initialization in LoadCursorA() called from
register_builtin_classes(). If the driver initialization initiated
in CreateDCW() goes in parallel with the initialization started
elsewhere without holding display_dc_section, the process can deadlock.

Fixes random lockup on start in Hammerting.
Signed-off-by: Paul Gofman <pgofman@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>