1.  Perform the Tuning Process at the HS400 target operating frequency.
    Latched the clock division value.
2.  if read transaction, then set the SDTIMNGCTL[FLW_CTL_BG].
3.  Switch to High Speed mode and then set the card clock frequency to
    a value not greater than 52Mhz
4.  Clear TBCTL[TB_EN],tuning block enable bit.
5.  Change to 8 bit DDR Mode
6.  Switch the card to HS400 mode.
7.  Set TBCTL[TB_EN], tuning block enable bit.
8.  Clear SYSCTL[SDCLKEN]
9.  Wait for PRSSTAT[SDSTB] to be set
10. Change the clock division to latched value.Set TBCTL[HS 400 mode]
    and Set SDCLKCTL[CMD_CLK_CTRL]
11. Set SYSCTL[SDCLKEN]
12. Wait for PRSSTAT[SDSTB] to be set
13. Set DLLCFG0[DLL_ENABLE] and DLLCFG0[DLL_FREQ_SEL].
14. Wait for delay chain to lock.
15. Set TBCTL[HS400_WNDW_ADJUST]
16. Again clear SYSCTL[SDCLKEN]
17. Wait for PRSSTAT[SDSTB] to be set
18. Set ESDHCCTL[FAF]
19. Wait for ESDHCCTL[FAF] to be cleared
20. Set SYSCTL[SDCLKEN]
21. Wait for PRSSTAT[SDSTB] to be set.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: Yinbo Zhu <yinbo.zhu@nxp.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>