arm64: dts: ti: k3-j784s4: Remove UART baud rate selection

arm64: dts: ti: k3-j784s4: Remove UART baud rate selection

As described in the binding document for the "current-speed" property:

"This should only be present in case a driver has no chance to know the
baud rate of the slave device."

This is not the case for the UART used in K3 devices, the current
baud-rate can be calculated from the registers. Having this property
has the effect of actually skipping the baud-rate setup in some drivers
as it assumes it will already be set to this rate, which may not always
be the case.

It seems this property's purpose was mistaken as selecting the desired
baud-rate, which it does not. It would have been wrong to select that
here anyway as DT is not the place for configuration, especially when
there are already more standard ways to set serial baud-rates.

Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20240326185441.29656-6-afd@ti.com
Signed-off-by: Nishanth Menon <nm@ti.com>