Hinlink-h88k: some fix to dts

[qbisi]

hdmi_rx tested and captured

v4l2-ctl --list-devices 
...
snps_hdmirx (platform:fdee0000.hdmi_receiver):
        /dev/video3
...

mmc speed fixed and tested

# cat /sys/kernel/debug/mmc0/ios 
clock:          200000000 Hz
actual clock:   187500000 Hz
vdd:            18 (3.0 ~ 3.1 V)
bus mode:       2 (push-pull)
chip select:    0 (don't care)
power mode:     2 (on)
bus width:      3 (8 bits)
timing spec:    10 (mmc HS400)
signal voltage: 1 (1.80 V)
driver type:    0 (driver type B)
# cat /sys/kernel/debug/mmc1/ios 
clock:          150000000 Hz
actual clock:   148500000 Hz
vdd:            21 (3.3 ~ 3.4 V)
bus mode:       2 (push-pull)
chip select:    0 (don't care)
power mode:     2 (on)
bus width:      2 (4 bits)
timing spec:    6 (sd uhs SDR104)
signal voltage: 1 (1.80 V)
driver type:    0 (driver type B)

also added a cd-gpio pin for sdmmc detection

cd-gpios = <&gpio0 RK_PA4 GPIO_ACTIVE_LOW>;

gpio and max mmc frequence are specified by vendor

[EvilOlaf]

lgtm