mtd: devices: add const qualifiers

Be a bit stricter and add few more 'const' qualifiers.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
index 8510ccb..a8caad2 100644
--- a/drivers/mtd/devices/docg3.c
+++ b/drivers/mtd/devices/docg3.c
@@ -123,7 +123,7 @@
 	doc_writeb(docg3, addr, DOC_FLASHADDRESS);
 }
 
-static char const *part_probes[] = { "cmdlinepart", "saftlpart", NULL };
+static char const * const part_probes[] = { "cmdlinepart", "saftlpart", NULL };
 
 static int doc_register_readb(struct docg3 *docg3, int reg)
 {