UBI: bugfix: allocate mandatory EBs first

First allocate the necessary eraseblocks, then the optional ones.
Otherwise it allocates all PEBs for bad EB handling, and fails
on then following EBA LEB allocation.
Reported-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

drivers/mtd/ubi/eba.c

@@ -1168,6 +1168,15 @@ int ubi_eba_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
 		}
 	}
 
+	if (ubi->avail_pebs < EBA_RESERVED_PEBS) {
+		ubi_err("no enough physical eraseblocks (%d, need %d)",
+			ubi->avail_pebs, EBA_RESERVED_PEBS);
+		err = -ENOSPC;
+		goto out_free;
+	}
+	ubi->avail_pebs -= EBA_RESERVED_PEBS;
+	ubi->rsvd_pebs += EBA_RESERVED_PEBS;
+
 	if (ubi->bad_allowed) {
 		ubi_calculate_reserved(ubi);
 
@@ -1184,15 +1193,6 @@ int ubi_eba_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
 		ubi->rsvd_pebs  += ubi->beb_rsvd_pebs;
 	}
 
-	if (ubi->avail_pebs < EBA_RESERVED_PEBS) {
-		ubi_err("no enough physical eraseblocks (%d, need %d)",
-			ubi->avail_pebs, EBA_RESERVED_PEBS);
-		err = -ENOSPC;
-		goto out_free;
-	}
-	ubi->avail_pebs -= EBA_RESERVED_PEBS;
-	ubi->rsvd_pebs += EBA_RESERVED_PEBS;
-
 	dbg_eba("EBA unit is initialized");
 	return 0;