drivers/edac: fix reset edac_mc pollmsec

This fixes a deadlock that could occur on a 'setup' and 'teardown' sequence of
the workq for a edac_mc control structure instance.  A similiar fix was
previously implemented for the edac_device code.

In addition, the edac_mc device code there was missing code to allow the workq
period valu to be altered via sysfs control.

This patch adds that fix on the code, and allows for the changing of the
period value as well.

Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/edac/edac_module.h b/drivers/edac/edac_module.h
index a2134df..3664ae9 100644
--- a/drivers/edac/edac_module.h
+++ b/drivers/edac/edac_module.h
@@ -52,6 +52,8 @@
 extern void edac_device_workq_teardown(struct edac_device_ctl_info *edac_dev);
 extern void edac_device_reset_delay_period(struct edac_device_ctl_info
 					   *edac_dev, unsigned long value);
+extern void edac_mc_reset_delay_period(int value);
+
 extern void *edac_align_ptr(void *ptr, unsigned size);
 
 /*