scsi: target: core: Fix warning on RT kernels

Calling spin_lock_irqsave() does not disable the interrupts on realtime
kernels, remove the warning and replace assert_spin_locked() with
lockdep_assert_held().

Signed-off-by: Maurizio Lombardi <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/target/target_core_tmr.c

···
 {
 	struct se_session *sess = se_cmd->se_sess;
 
-	assert_spin_locked(&sess->sess_cmd_lock);
-	WARN_ON_ONCE(!irqs_disabled());
+	lockdep_assert_held(&sess->sess_cmd_lock);
+
 	/*
 	 * If command already reached CMD_T_COMPLETE state within
 	 * target_complete_cmd() or CMD_T_FABRIC_STOP due to shutdown,