Input: drivers/joystick - fix various sparse warnings

Fix various issues pointed by sparse:
 - module_param_array_named() takes unsigned int as number
   of parameters argument
 - shadowing of global variables is not healthy. I think there was
   once a bug in db9 caused by it.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/joystick/analog.c b/drivers/input/joystick/analog.c
index 1c1afb5..bdd157c 100644
--- a/drivers/input/joystick/analog.c
+++ b/drivers/input/joystick/analog.c
@@ -53,7 +53,7 @@
 #define ANALOG_PORTS		16
 
 static char *js[ANALOG_PORTS];
-static int js_nargs;
+static unsigned int js_nargs;
 static int analog_options[ANALOG_PORTS];
 module_param_array_named(map, js, charp, &js_nargs, 0);
 MODULE_PARM_DESC(map, "Describes analog joysticks type/capabilities");