rv/dot2K: add 'static' qualifier for local variable

Following Daniel's suggestion, fix similar warning
in template files, which would prevent new monitors
from such warning.

Link: https://lkml.kernel.org/r/20220824034357.2014202-3-zengheng4@huawei.com



Cc: <mingo@redhat.com>
Fixes:	24bce201 ("tools/rv: Add dot2k")
Suggested-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>