MIPS: JZ4740: Use PWM lookup table

Associate the PWM with the pwm-beeper device using a PWM lookup table.
This will eventually allow the legacy function calls to pwm_request() to
be removed from all consumer drivers.

Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11261/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>