edac: add edac_device_alloc_index()

Add edac_device_alloc_index(), because for MAPLE platform there may
exist several EDAC driver modules that could make use of
edac_device_ctl_info structure at the same time. The index allocation
for these structures should be taken care of by EDAC core.

[akpm@linux-foundation.org: cleanups]
Signed-off-by: Harry Ciao <qingtao.cao@windriver.com>
Cc: Doug Thompson <norsk5@yahoo.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/edac/edac_core.h b/drivers/edac/edac_core.h
index 48d3b14..3493c6b 100644
--- a/drivers/edac/edac_core.h
+++ b/drivers/edac/edac_core.h
@@ -841,6 +841,7 @@
 				int inst_nr, int block_nr, const char *msg);
 extern void edac_device_handle_ce(struct edac_device_ctl_info *edac_dev,
 				int inst_nr, int block_nr, const char *msg);
+extern int edac_device_alloc_index(void);
 
 /*
  * edac_pci APIs