clk: rockchip: clk_rk3288: add PCLK_RKPWM

The rk3288 pwm nodes synced from Linux make use of PCLK_RKPWM
instead of PCLK_PWM. They have the same pclk_cpu parent,
so add PCLK_RKPWM to rk3288_clk_get_rate().

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>  # chromebook-jerry
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/drivers/clk/rockchip/clk_rk3288.c b/drivers/clk/rockchip/clk_rk3288.c
index 3b29992..ef744c0 100644
--- a/drivers/clk/rockchip/clk_rk3288.c
+++ b/drivers/clk/rockchip/clk_rk3288.c
@@ -778,6 +778,7 @@
 	case PCLK_I2C5:
 		return gclk_rate;
 	case PCLK_PWM:
+	case PCLK_RKPWM:
 		return PD_BUS_PCLK_HZ;
 	case SCLK_SARADC:
 		new_rate = rockchip_saradc_get_clk(priv->cru);