UBI: fix error message and compilation warnings

Fix the followong compilation warnings introduced by commit
095751a6:

drivers/mtd/ubi/scan.c: In function 'check_what_we_have':
drivers/mtd/ubi/scan.c:960: warning: passing argument 1 of 'get_random_bytes' discards qualifiers from pointer target type

Fix the following compilation warnings introduced by commit
1a49af2c:

drivers/mtd/ubi/io.c: In function 'ubi_io_read':
drivers/mtd/ubi/io.c:153: warning: initialization makes integer from pointer without a cast
drivers/mtd/ubi/io.c:170: warning: format '%s' expects type 'char *', but argument 5 has type 'int'
drivers/mtd/ubi/io.c:177: warning: format '%zd' expects type 'signed size_t', but argument 7 has type 'int'
drivers/mtd/ubi/io.c:177: warning: too many arguments for format

Also, amend the ECC error code string and add brackets and whitespace
there - this should make the message readable.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

drivers/mtd/ubi/io.c

@@ -150,7 +150,7 @@ int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 retry:
 	err = ubi->mtd->read(ubi->mtd, addr, len, &read, buf);
 	if (err) {
-		const char errstr = (err == -EBADMSG) ? "ECC error" : "";
+		const char *errstr = (err == -EBADMSG) ? " (ECC error)" : "";
 
 		if (err == -EUCLEAN) {
 			/*
@@ -174,7 +174,7 @@ int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 			goto retry;
 		}
 
-		ubi_err("error %d while reading %d bytes from PEB %d:%d, "
+		ubi_err("error %d%s while reading %d bytes from PEB %d:%d, "
 			"read %zd bytes", err, errstr, len, pnum, offset, read);
 		ubi_dbg_dump_stack();
 

drivers/mtd/ubi/scan.c

@@ -901,8 +901,7 @@ static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
  * MTD device. Returns zero if we should proceed with attaching the MTD device,
  * and %-EINVAL if we should not.
  */
-static int check_what_we_have(const struct ubi_device *ubi,
-			      struct ubi_scan_info *si)
+static int check_what_we_have(struct ubi_device *ubi, struct ubi_scan_info *si)
 {
 	struct ubi_scan_leb *seb;
 	int max_corr;