staging: wilc1000: rename drvHandler in wilc_wlan_cfg_get function

This patch rename drvHandler to drv_handler that is fifth argument of
wilc_wlan_cfg_get function to avoid camelcase.

Signed-off-by: Leo Kim <leo.kim@atmel.com>
Signed-off-by: Glen Lee <glen.lee@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>