[ Upstream commit 68a213d3 ]

This machine reports number of keyboard backlight led levels, instead of
value of the last led level index. Therefore max_brightness properly needs
to be subtracted by 1 to match led max_brightness API.
Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Reported-by: Gabriel M. Elder <gabriel@tekgnowsys.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=196913Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>