iscsi-target: Remove unused variables in iscsi_target_parameters.c

local_right_val was an obvious case, tmp_ptr is also write-only, but
evades the compiler by being passed to simple_strtoul as char **endp.

Signed-off-by: Joern Engel <joern@logfs.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>