drm/amd/pm/smu11: Prevent division by zero

drm/amd/pm/smu11: Prevent division by zero

commit 7ba88b5cccc1a99c1afb96e31e7eedac9907704c upstream.

The user can set any speed value.
If speed is greater than UINT_MAX/8, division by zero is possible.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 1e866f1fe528 ("drm/amd/pm: Prevent divide by zero")
Signed-off-by: Denis Arefev <arefev@swemel.ru>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit da7dc714a8f8e1c9fc33c57cd63583779a3bef71)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>