coccinelle: irqf_oneshot: reduce the severity due to false positives

The IRQF_ONESHOT should be present for threaded IRQ using default
primary handler.  However intetrupt of many child devices, e.g. children
of MFD, is nested thus the IRQF_ONESHOT is not needed.  The coccinelle
message about error misleads submitters and reviewers about the severity
of the issue, so make it a warning and mention possible false positive.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>

scripts/coccinelle/misc/irqf_oneshot.cocci

@@ -103,11 +103,11 @@ devm_request_threaded_irq@p(dev, irq, NULL, ...)
 @script:python depends on org@
 p << match.p;
 @@
-msg = "ERROR: Threaded IRQ with no primary handler requested without IRQF_ONESHOT"
+msg = "WARNING: Threaded IRQ with no primary handler requested without IRQF_ONESHOT (unless it is nested IRQ)"
 coccilib.org.print_todo(p[0],msg)
 
 @script:python depends on report@
 p << match.p;
 @@
-msg = "ERROR: Threaded IRQ with no primary handler requested without IRQF_ONESHOT"
+msg = "WARNING: Threaded IRQ with no primary handler requested without IRQF_ONESHOT (unless it is nested IRQ)"
 coccilib.report.print_report(p[0],msg)