phy: amlogic: meson8b-usb2: Don't set REG_ADP_BC_ACA_ENABLE on Meson8

Skip setting REG_ADP_BC_ACA_ENABLE on Meson8 SoCs and polling for the
REG_ADP_BC_ACA_PIN_FLOAT bit. The vendor also skips this part on Meson8
SoCs.
This fixes initialization of the host-only USB PHY on Meson8 which would
otherwise fail with "USB ID detect failed!".

Fixes: 4a3449d1

 ("phy: meson8b-usb2: add support for the USB PHY on Meson8 SoCs")
Reported-by: Thomas Graichen <thomas.graichen@gmail.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Thomas Graichen <thomas.graichen@gmail.com>
Link: https://lore.kernel.org/r/20200512222424.549351-5-martin.blumenstingl@googlemail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>