rv: Refactor da_monitor to minimise macros

rv: Refactor da_monitor to minimise macros

The da_monitor helper functions are generated from macros of the type:

DECLARE_DA_FUNCTION(name, type) \
static void da_func_x_##name(type arg) {} \
static void da_func_y_##name(type arg) {} \

This is good to minimise code duplication but the long macros made of
skipped end of lines is rather hard to parse. Since functions are
static, the advantage of naming them differently for each monitor is
minimal.

Refactor the da_monitor.h file to minimise macros, instead of declaring
functions from macros, we simply declare them with the same name for all
monitors (e.g. da_func_x) and for any remaining reference to the monitor
name (e.g. tracepoints, enums, global variables) we use the CONCATENATE
macro.
In this way the file is much easier to maintain while keeping the same
generality.
Functions depending on the monitor types are now conditionally compiled
according to the value of RV_MON_TYPE, which must be defined in the
monitor source.
The monitor type can be specified as in the original implementation,
although it's best to keep the default implementation (unsigned char) as
not all parts of code support larger data types, and likely there's no
need.

We keep the empty macro definitions to ease review of this change with
diff tools, but cleanup is required.

Also adapt existing monitors to keep the build working.

Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20251126104241.291258-2-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>