mmc: sdhci-xenon: Fix default value of LOGIC_TIMING_ADJUST for eMMC5.0 PHY

The default value of LOGIC_TIMING_ADJUST register in eMMC 5.0 PHY is
different from that in eMMC 5.1 PHY.  Set the specific value for that
register in eMMC 5.0 PHY.

Signed-off-by: Hu Ziji <huziji@marvell.com>
Reported-by: Jisheng Zhang <jszhang@marvell.com>
Tested-by: Jisheng Zhang <jszhang@marvell.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>