thinkpad-acpi: move greeting messages out of the first subdriver (v2)

Move the driver initial greetings out of the first subdriver, as we do a
lot of other initialization before that point, and the initial greetings
should go as soon as the driver decides that it should load.

These greetings are not cosmetic, they make my life easier when users
report bugs.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>