Revert "board: zynqmp: Fix for wrong AMS setting by ROM"

Revert "board: zynqmp: Fix for wrong AMS setting by ROM"

This reverts commit dfbe492edef421de09617dc26805fc428440924e.
Analog bus control register should be programmed in SPL only. This commit
3414712ba8a ("arm64: zynqmp: Writing correct value to ANALOG_BUS") is
programming the same. So revert this commit.

Signed-off-by: T Karthik Reddy <t.karthik.reddy@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/215bc936e36f88d2e7c4422ec68cad6d40cb8f68.1645624892.git.michal.simek@xilinx.com