clk: qcom: clk-alpha-pll: Update the steps to slew the Lucid PLL

When PLL HW_UPDATE_LOGIC_BYPASS bit is not set then PLL can be
updated dynamically by setting the PLL_UPDATE bit in mode register
and hardware would clear the PLL_UPDATE automatically when
PLL_ACK_LATCH is asserted.

Change-Id: I1c568c9fdd37a554d71fc5c3d840a71e983baf60
Signed-off-by: Taniya Das <tdas@codeaurora.org>