Revert "pll: zynqmp: Remove the disable for pll"

Revert "pll: zynqmp: Remove the disable for pll"

With the current pmufw the disable of pll does not seem to work as
expected, ie disable once all the dependent clocks
are disabled. So revert the 18b0413295bae59f9db09aa459e27fd1ffbfa9b4
(pll disable) for now. Eventually once the pmufw
ref-counting happens correctly we can go remove the pll stuff from
linux.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: Hyun Kwon <hyun.kwon@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>