UBI: make tests modes dynamic

Similarly to the debugging checks and message, make the test modes
be dynamically selected via the "debug_tsts" module parameter or
via the "/sys/module/ubi/parameters/debug_tsts" sysfs file. This
is consistent with UBIFS as well.

And now, since all the Kconfig knobs became dynamic, we can remove
the Kconfig.debug file completely.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/drivers/mtd/ubi/debug.c b/drivers/mtd/ubi/debug.c
index 4c7a3f6..d4d07e5 100644
--- a/drivers/mtd/ubi/debug.c
+++ b/drivers/mtd/ubi/debug.c
@@ -32,12 +32,15 @@
 
 unsigned int ubi_msg_flags;
 unsigned int ubi_chk_flags;
+unsigned int ubi_tst_flags;
 
 module_param_named(debug_msgs, ubi_msg_flags, uint, S_IRUGO | S_IWUSR);
 module_param_named(debug_chks, ubi_chk_flags, uint, S_IRUGO | S_IWUSR);
+module_param_named(debug_tsts, ubi_chk_flags, uint, S_IRUGO | S_IWUSR);
 
 MODULE_PARM_DESC(debug_msgs, "Debug message type flags");
 MODULE_PARM_DESC(debug_chks, "Debug check flags");
+MODULE_PARM_DESC(debug_tsts, "Debug special test flags");
 
 /**
  * ubi_dbg_dump_ec_hdr - dump an erase counter header.