firmware: send -EINTR on signal abort on fallback mechanism
Right now we send -EAGAIN to a syfs write which got interrupted.
Userspace can't tell what happened though, send -EINTR if we
were killed due to a signal so userspace can tell things apart.
This is only applicable to the fallback mechanism.
Reported-by: Martin Fuzzey <mfuzzey@parkeon.com> Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>