sb_edac: Mark get_mci_for_node_id as static

This patch marks the function get_mci_for_node_id() as static because it
is not used outside of sb_edac.c.

Thus, it also eliminates the following warning:
drivers/edac/sb_edac.c:918:22: warning: no previous prototype for ‘get_mci_for_node_id’ [-Wmissing-prototypes]
Signed-off-by: NRashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Link: http://lkml.kernel.org/r/0441f508186fc4eeabc8e9c3e4dde013d99405d4.1387029387.git.rashika.kheria@gmail.comSigned-off-by: NBorislav Petkov <bp@suse.de>

drivers/edac/sb_edac.c

@@ -915,7 +915,7 @@ static void get_memory_layout(const struct mem_ctl_info *mci)
 	}
 }
 
-struct mem_ctl_info *get_mci_for_node_id(u8 node_id)
+static struct mem_ctl_info *get_mci_for_node_id(u8 node_id)
 {
 	struct sbridge_dev *sbridge_dev;