mips: Remove BKL from tb0219

cycle_kernel_lock() was added during the big BKL pushdown. It should
ensure the serializiation against driver init code.

tb0219_base is initialized before the character device is
registered, but the spinlock is not initialized.

Initialize the spinlock statically and remove cycle_kernel_lock().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <20091010153350.222654356@linutronix.de>
Cc: Yoichi Yuasa <yuasa@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>