phy: marvell: a3700: revise the USB3 comphy setting during power on

phy: marvell: a3700: revise the USB3 comphy setting during power on

This commit is based on commit d9899826 by
  zachary <zhangzg@marvell.com>
from u-boot-marvell, see
github.com/MarvellEmbeddedProcessors/u-boot-marvell/commit/d9899826

- According to design specification, the transmitter should be set to high
  impedence mode during electrical idle. Thus transmitter should detect RX
  at high impedence mode also, and delay is needed to accommodate high
  impedence off latency. Otherwise the USB3 will have detection issue that
  most of the time the USB3 device can not be detected at all, or be
  detected as USB2 device sometimes.
  Modified registers: RD005C302h (R181h) (0051h) Lane Configuration 1
  Bit 6: set to 1 to let Tx detect Rx at HiZ mode
  Bit [3:4]: set to 2 to be delayed by 2 clock cycles
  Bit 0: set to 1 to set transmitter to high impedance mode during idle.
- USB3 De-emphasize level of -3.5dB is mandatory, but USB3 MAC selects 0x2
  (emphasize disabled) in the MAC_PHY_TXDEEMPH [1:0], while it is supposed
  to select 0x1(3.5dB emphasize). Thus need to override what comes from
  the MAC(by setting register 0x1c2 bit2 to 0x1) and to configure the
  overridded values of MAC_PHY_TXDEEMPH [1:0] to 0x1(bit15 of register
  0x181 and bit0 of register 0x180).
- According to USB3 application note, need to update below comphy
  registers:
  Set max speed generation to USB3.0 5Gbps(set RD005C04Ah bit[11:10] to 1)
  Set capacitor value to 0xF(set RF005C224 bit[3:0] to 0xF)

Signed-off-by: Marek Behun <marek.behun@nic.cz>
Signed-off-by: Stefan Roese <sr@denx.de>