irq_work: Fix checking of IRQ_WORK_LAZY flag set on non PREEMPT_RT

[ Upstream 4.19-rt commit a854c3525b7082189996a41c1dc057dcb138e305 ]

When CONFIG_PREEMPT_RT_FULL is not set, some of the checks for using
lazy_list are not properly made as the IRQ_WORK_LAZY is not checked. There's
two locations that need this update, so a use_lazy_list() helper function is
added and used in both locations.

Link: https://lore.kernel.org/r/20200321230028.GA22058@duo.ucw.cz
Reported-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
[ported to 4.4]
Signed-off-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Daniel Wagner <dwagner@suse.de>