serial: TTY: new ldiscs for staging

Push the max ldiscs by a few number to allow ldiscs
to exist in the staging directory and elsewhere.
Signed-off-by: NPavan Savoy <pavan_savoy@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

include/linux/tty.h

@@ -23,7 +23,7 @@
  */
 #define NR_UNIX98_PTY_DEFAULT	4096      /* Default maximum for Unix98 ptys */
 #define NR_UNIX98_PTY_MAX	(1 << MINORBITS) /* Absolute limit */
-#define NR_LDISCS		21
+#define NR_LDISCS		30
 
 /* line disciplines */
 #define N_TTY		0