MIPS: JZ4740: Remove unused linux/leds_pwm.h include

The board code never sets up a leds-pwm device, so including the header
is not necessary.

Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
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/11262/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>