[U-Boot] rockchip: missing request op in common pinctrl driver resulting kernel boot failure

[djw at t-chip.com.cn]

Since this request is a no-op, it is best to drop the
pinctrl_request_noflags(pinctrl, PERIPH_ID_PWM?) lines in
board/rockchip/evb_rk3399/evb-rk3399.c (there're no such code lines in other
rk3399 board files), which is tested to work with the Firefly-RK3399 board.

Therefore, are the PERIPH_ID_PWM? taken care of somewhere in other places?

--
Best Regards,
Levin Du