dyndbg: no vpr-info on empty queries

when `echo $cmd > control` contains multiple queries, extra query
separators (;\n) can parse as empty statements.  This is normal, and a
vpr-info on an empty command is just noise.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Link: https://lore.kernel.org/r/20211013220726.1280565-4-jim.cromie@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>