rv: Set variable 'da_mon_##name' to static

rv: Set variable 'da_mon_##name' to static

gcc with W=1 reports
kernel/trace/rv/monitors/wip/wip.c:20:1: sparse: sparse: symbol 'da_mon_wip' was not declared. Should it be static?

The per-cpu variable 'da_mon_##name' is only used in its defining file, so
it should be static.

Link: https://lore.kernel.org/linux-trace-kernel/20230823020051.3184953-1-liaoyu15@huawei.com
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202307280030.7EjUG9gR-lkp@intel.com/
Signed-off-by: Yu Liao <liaoyu15@huawei.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>