The lvm2 package lists thin-provisioning-tools as a suggested package rather than "Depends", this is because thin-provisioning-tools is in the universe archive (Community supported) and lvm2 is in the main archive (Canonical supported). So, when you install lvm2 you should see thin-provisioning-tools under "suggested packages", and you have to separately list thin-provisioning-tools on the command line when you install lvm2. This is the case for all architectures not just for Power.
The lvm2 package lists thin-provisioni ng-tools as a suggested package rather than "Depends", this is because thin-provisioni ng-tools is in the universe archive (Community supported) and lvm2 is in the main archive (Canonical supported). So, when you install lvm2 you should see thin-provisioni ng-tools under "suggested packages", and you have to separately list thin-provisioni ng-tools on the command line when you install lvm2. This is the case for all architectures not just for Power.