drm/nouveau/therm: remove ineffective workarounds for alarm bugs

drm/nouveau/therm: remove ineffective workarounds for alarm bugs

BugLink: http://bugs.launchpad.net/bugs/1694621
commit e4311ee51d1e2676001b2d8fcefd92bdd79aad85 upstream.

These were ineffective due to touching the list without the alarm lock,
but should no longer be required.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>