target-core: don't use "const char*" for a buffer that is written to

iscsi_parse_pr_out_transport_id launders the const away via a call to
strstr(), and then modifies the buffer (writing a nul byte) through
the return value. It's cleaner to be honest and simply declare the
parameter as "char*", fixing up the call chain, and allowing us to
drop the cast in the return statement.

Amusingly, the two current callers found it necessary to cast a
non-const pointer to a const.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
index b024613..01ac306 100644
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c
@@ -1601,7 +1601,7 @@ core_scsi3_decode_spec_i_port(
 			dest_rtpi = tmp_lun->lun_rtpi;
 
 			i_str = target_parse_pr_out_transport_id(tmp_tpg,
-					(const char *)ptr, &tid_len, &iport_ptr);
+					ptr, &tid_len, &iport_ptr);
 			if (!i_str)
 				continue;
 
@@ -3287,7 +3287,7 @@ core_scsi3_emulate_pro_register_and_move(struct se_cmd *cmd, u64 res_key,
 		goto out;
 	}
 	initiator_str = target_parse_pr_out_transport_id(dest_se_tpg,
-			(const char *)&buf[24], &tmp_tid_len, &iport_ptr);
+			&buf[24], &tmp_tid_len, &iport_ptr);
 	if (!initiator_str) {
 		pr_err("SPC-3 PR REGISTER_AND_MOVE: Unable to locate"
 			" initiator_str from Transport ID\n");