mmc: sdhci-cadence: import updates from Linux 4.12

mmc: sdhci-cadence: import updates from Linux 4.12

This driver is a counterpart of drivers/mmc/host/sdhci-cadence.c
from Linux.  Some updates for v4.12-rc1 can be imported to U-Boot.

 - Fix value of SDHCI_CDNS_HRS04_RDATA_SHIFT
 - Add polling for ACK bit to be sure that data are written to
   the PHY register
 - Retrieve PHY values from DT properties instead of fixed data

The following is the list of upstream commits:

 - Linux commit 4e03f628b464e0580abadf5161eaa38c61d20943
   mmc: sdhci-cadence: fix bit shift of read data from PHY port

 - Linux commit a0f8243229ed071c8da0ea7cedc1b7bf1b1515da
   mmc: sdhci-cadence: Fix writing PHY delay

 - Linux commit a89c472d8b55c5afc4c79e6e3d1338730034eb01
   mmc: sdhci-cadence: Update PHY delay configuration

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>