UBI: fix warnings

Old gcc complains:

CC      drivers/mtd/ubi/wl.o
drivers/mtd/ubi/wl.c: In function 'wear_leveling_worker':
drivers/mtd/ubi/wl.c:746: warning: 'pe' may be used uninitialized in this function
CC      drivers/mtd/ubi/scan.o
drivers/mtd/ubi/scan.c: In function 'ubi_scan':
drivers/mtd/ubi/scan.c:772: warning: 'ec' may be used uninitialized in this function
drivers/mtd/ubi/scan.c:772: note: 'ec' was declared here
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

drivers/mtd/ubi/scan.c

@@ -773,7 +773,7 @@ struct ubi_scan_leb *ubi_scan_get_free_peb(struct ubi_device *ubi,
  */
 static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si, int pnum)
 {
-	long long ec;
+	long long uninitialized_var(ec);
 	int err, bitflips = 0, vol_id, ec_corr = 0;
 
 	dbg_bld("scan PEB %d", pnum);

drivers/mtd/ubi/wl.c

@@ -743,7 +743,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
 				int cancel)
 {
 	int err, put = 0, scrubbing = 0, protect = 0;
-	struct ubi_wl_prot_entry *pe;
+	struct ubi_wl_prot_entry *uninitialized_var(pe);
 	struct ubi_wl_entry *e1, *e2;
 	struct ubi_vid_hdr *vid_hdr;