staging: wilc1000: remove pointer variables of txq_add_to_head_cs

This patch removes txq_add_to_head_critical_section and txq_add_to_head_lock
which are pointer of g_linux_wlan->txq_add_to_head_cs.
Just use g_linux_wlan->txq_add_to_head_cs as argument of function.

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