Input: serio - fix potential deadlock when unbinding drivers
sysfs_remove_group() waits for sysfs attributes to be removed, therefore
we do not need to worry about driver-specific attributes being accessed
after driver has been detached from the device. In fact, attempts to take
serio->drv_mutex in attribute methods may lead to the following deadlock:
Fix this by removing calls to serio_[un]pin_driver() and functions themselves
and using driver-private mutexes to serialize access to attribute's set()
methods that may change device state.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>