mtd: partitions: make parsers return 'const' partition arrays

We only want to modify these arrays inside the parser "drivers", so the
drivers should construct them however they like, then return them as
immutable arrays.

This will make other refactorings easier.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
diff --git a/drivers/mtd/bcm63xxpart.c b/drivers/mtd/bcm63xxpart.c
index cf02135..4409369 100644
--- a/drivers/mtd/bcm63xxpart.c
+++ b/drivers/mtd/bcm63xxpart.c
@@ -68,7 +68,7 @@
 }
 
 static int bcm63xx_parse_cfe_partitions(struct mtd_info *master,
-					struct mtd_partition **pparts,
+					const struct mtd_partition **pparts,
 					struct mtd_part_parser_data *data)
 {
 	/* CFE, NVRAM and global Linux are always present */