arm64: zynqmp: Writing correct value to ANALOG_BUS

The default register configuration after powerup for PSSYSMON_ANALOG_BUS
register is incorrect. Hence, fix this in SPL by writing correct fixed
value. It follows UG1085 chapter 'PS SYSMON Analog_Bus' and reflects commit
sw_apps:zynq ("056ca65d44549ce27f716d423e8dfdefeee7440c")
in Xilinx:embeddedsw[1].

[1] https://github.com/Xilinx/embeddedsw



Signed-off-by: Adrian Fiergolski <adrian.fiergolski@fastree3d.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>