CLK_TOPSW_LSBUS is parent of WDT clock. Clock from invalid
clock list would not be registered to CCF framework and so
cannot be used as parent of other clocks.

WDT clock has default parent as CLK_TOPSW_LSBUS(APB clock).
If CLK_TOPSW_LSBUS is not registered, CCF would not recognize
that clock and hence rate of WDT clock would be calculated to
be 0 by CCF(as parent rate is considered 0).

So it is necessary to allow registration of CLK_TOPSW_LSBUS
clock.

Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
Signed-off-by: Jolly Shah <jolly.shah@xilinx.com>
Change-Id: Iceaba0f137784fc5fd666e66ffc4c143381c6ccc