w1: ds2482: make module parameter extra_config static

The variable extra_config is local to the source and does not
need to be in global scope, so make it static.

Cleans up sparse warning:
warning: symbol 'extra_config' was not declared. Should it be static?
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/w1/masters/ds2482.c

@@ -71,7 +71,7 @@ MODULE_PARM_DESC(active_pullup, "Active pullup (apply to all buses): " \
 #define DS2482_REG_CFG_APU		0x01	/* active pull-up */
 
 /* extra configurations - e.g. 1WS */
-int extra_config;
+static int extra_config;
 
 /**
  * Write and verify codes for the CHANNEL_SELECT command (DS2482-800 only).