dyndbg: fix pr_err with empty string

this pr_err attempts to print the string after the OP, but the string
has been parsed and chopped up, so looks empty.

Acked-by:  <jbaron@akamai.com>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Link: https://lore.kernel.org/r/20200719231058.1586423-9-jim.cromie@gmail.com


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