Fix shutdown regression introduced with 3e737241ba ("linux-postmarketos-omap:
N900: disable twl off idle features"). After that commit, shutdown never
completes.
[ci:skip-build]: Already built successfully in CI
Disable twl pmic off-idle configuration for Nokia N900. An ugly patch to do
this was lost during the migration from linux-nokia-n900 to the shared omap
kernel.
Fixes#2161
[ci:skip-build]: Already built successfully in CI