ARM: dts: everest: Add phase corrections for eMMC

ARM: dts: everest: Add phase corrections for eMMC

The values were determined experimentally via boot tests, not by
measuring the bus behaviour with a scope. We plan to do scope
measurements to confirm or refine the values and will update the
devicetree if necessary once these have been obtained.

However, with the patch we can write and read data without issue, where
as booting the system without the patch failed at the point of mounting
the rootfs.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Link: https://lore.kernel.org/r/20210628013605.1257346-1-andrew@aj.id.au
Fixes: 2fc88f92359d ("mmc: sdhci-of-aspeed: Expose clock phase controls")
Fixes: a5c5168478d7 ("ARM: dts: aspeed: Add Everest BMC machine")
Signed-off-by: Joel Stanley <joel@jms.id.au>