clk: qcom: clk-alpha-pll: Update the list_registers ops for all PLLs

Update list_register operation to read the pll offset defined in PLL
register map to avoid mismatch across various targets.

Change-Id: Iab536c49a8e621c0ebd8c5fe7a43fa7aa42671b8
Signed-off-by: Naveen Yadav <naveenky@codeaurora.org>