ArmPkg/PlatformBootManagerLib: don't connect all devices on each boot

ArmPkg/PlatformBootManagerLib: don't connect all devices on each boot

In order to avoid boot delays from devices such as network controllers
that may not even be involved in booting at all, drop the call to
EfiBootManagerConnectAll () from the boot path. It will be called by
UiApp, so when going through the menu, all devices will be connected
as usual, but for the default boot, it is really not necessary so
let's get rid of this.

Enumerating all possible boot options and creating Boot#### variables
for them is equally unnecessary in the default case, and also happens
automatically in UiApp, so drop that as well.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>