target: fixup error message in target_tg_pt_gp_alua_access_type_store()

When setting up a target the error message:

Unable to do set ##_name ALUA state on non valid tg_pt_gp ID: 0

is displayed.
Apparently concatenation doesn't work in a string; one should be using
implicit string concatenation here.
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_configfs.c

@@ -2545,7 +2545,7 @@ static ssize_t target_tg_pt_gp_alua_support_##_name##_store(		\
 	int ret;							\
 									\
 	if (!t->tg_pt_gp_valid_id) {					\
-		pr_err("Unable to do set ##_name ALUA state on non"	\
+		pr_err("Unable to do set " #_name " ALUA state on non"	\
 		       " valid tg_pt_gp ID: %hu\n",			\
 		       t->tg_pt_gp_valid_id);				\
 		return -EINVAL;						\