Remove prompts from Kconfig options `UART_x_NRF_UART*` that select
the type of nrfx driver (for UART or UARTE peripheral) to be used
for a given instance. This prevents the options from being modified
from configuration files.
Instead, make one of these options selected by default according to the
"compatible" property set for the corresponding UART node in devicetree.
This eliminates the need of changing both the "compatible" property in
devicetree and the Kconfig option selecting the driver type when a user
wants to switch between UART and UARTE for a given instance.
Since all `UART_x_NRF_UART*` options are made "hidden" by this commit,
all their occurrences in configuration files are removed.
Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>
97b07b943a