wl1251: fix oops on early interrupt

This driver disables interrupt just after requesting it and enables it
later, after interface is up. However currently there is a time window
between request_irq() and disable_irq() where if interrupt arrives, the
driver oopses because it's not yet ready to process it. This can be
reproduced by inserting the module, associating and removing the module
multiple times.

Eliminate this race by setting IRQF_NOAUTOEN flag before request_irq().

Cc: stable@vger.kernel.org # v2.6.37+
Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>