mod/ppu_v1: Set cluster PPU to be in dynamic mode

In this patch the cluster PPU can be configured to be set to
dynamic mode and locked on cluster transition to ON state.

A configuration parameter is added to enable or disable this behavior
as some platforms may not support it.

Signed-off-by: Ahmed Gadallah <ahmed.gadallah@arm.com>
Change-Id: I0732362fdf786e3673806b48ecc30e38f861ad20