dt-bindings: mmc: sdhci-am654: Add compatible string for AM64 SoC

Add compatible string for AM64 SoC in device tree binding of AM654 SDHCI module
as the same IP is used.

Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210113115908.3882-2-a-govindraju@ti.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>