Quite some time ago special handling for tablets was added to
gsd-power-manager to automatically suspend the tablet when the
screen was blanked to save power.

With the more recent auto-suspend (when on battery power) support, this
hardcoded behavior really is no longer necessary, if the auto-suspend
timeout gets set to the same value as the blank timeout the same result
is achieved, but now under user control, rather then being hardcoded.

Not having this hardcoded is desirable because suspend is not always
desirable, e.g. when ongoing downloads are active, or other network
connections are open such as an irc client.

The hardcoded behavior is especially troublesome because it not only
triggers on actual tablets, but also on various non tablet devices,
both surface like devices, which are often used as one would use a
laptop, as well as on some actual laptops. On laptops one may typically
have an irc-client open, network downloads ongoing, etc. and then lock
the screen when walking away. The current hardcoded suspend behavior
causes the downloads to abort, irc messages to be missed, etc. and
with this not being configurable there is nothing the user can do to
avoid this.

I've looked into making gsd_power_is_hardware_a_tablet() more reliable,
but this relies on the DMI chassis type, which ultimately simply is
unreliable

Since the auto-suspend on screen blank functionality is duplicate with
the auto-suspend and the tablet-identification is unreliable, lets just
remove the special handling for tablets.