[PATCH] generic_serial.h: kill incorrect gs_debug reference

generic_serial.h contained an incorrect extern reference to the static
variable gs_debug (Benoit Boissinot reported that gcc 4.0 rejects this).
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/generic_serial.h

@@ -91,6 +91,4 @@ int  gs_setserial(struct gs_port *port, struct serial_struct __user *sp);
 int  gs_getserial(struct gs_port *port, struct serial_struct __user *sp);
 void gs_got_break(struct gs_port *port);
 
-extern int gs_debug;
-
 #endif