compat: backport upstream firmware_class bug through f45f3c1f

compat: backport upstream firmware_class bug through f45f3c1f

This backports this patch:

commit f45f3c1f3f616ca1d1e1eb5e7a720ca63cb59550
Author: Johannes Berg <johannes.berg@intel.com>
Date:   Wed Aug 18 17:15:18 2010 +0200

    firmware_class: fix typo in error path

    In the error path, _request_firmware sets
    firmware_p to NULL rather than *firmware_p,
    which leads to passing a freed firmware
    struct to drivers when the firmware file
    cannot be found. Fix this.

    Broken by commit f8a4bd3456b988fc73b2c.

    Reported-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
    Signed-off-by: Johannes Berg <johannes.berg@intel.com>
    Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
    Signed-off-by: Pekka Enberg <penberg@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
All kernels older than 2.6.33 would be affected by this.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>