This patch adds LPD WDT clock node to the pm_clock clocks structure list
so that LPD WDT can be used from Linux.

Also this patch removes the CLK_LPD_LSBUS from invalid clock list to
allow the registration of this clock to CCF framework as it is the
parent of LPD WDT.

Signed-off-by: Mounika Grace Akula <mounika.grace.akula@xilinx.com>
Signed-off-by: Jolly Shah <jolly.shah@xilinx.com>
Change-Id: Iea065aa8150eaba4bb4b42bc6be1fd4b7fe7b403