dt-bindings: mmc: sdhci-am654: fix compatible for j7200

On TI J7200 SoC the SDHCI controller compatible defined as
 "ti,j7200-sdhci-8bit", "ti,j721e-sdhci-8bit"
 or
 "ti,j7200-sdhci-4bit", "ti,j721e-sdhci-4bit"
which causes dtbs_check warnings:
mmc@4f80000: compatible: ['ti,j7200-sdhci-8bit', 'ti,j721e-sdhci-8bit'] is too long
mmc@4f80000: compatible: Additional items are not allowed ('ti,j721e-sdhci-8bit' was unexpected)
mmc@4fb0000: compatible:0: 'ti,j7200-sdhci-4bit' is not one of ['ti,am654-sdhci-5.1', 'ti,j721e-sdhci-8bit',
 'ti,j721e-sdhci-4bit', 'ti,j7200-sdhci-8bit', 'ti,j721e-sdhci-4bit', 'ti,am64-sdhci-8bit', 'ti,am64-sdhci-4bit']
mmc@4fb0000: compatible: ['ti,j7200-sdhci-4bit', 'ti,j721e-sdhci-4bit'] is too long
mmc@4fb0000: compatible: Additional items are not allowed ('ti,j721e-sdhci-4bit' was unexpected)

Fix it by adding missing compatible strings and their combinations.

Fixes: 407d0c2c

 ("dt-bindings: mmc: sdhci-am654: Convert sdhci-am654 controller documentation to json schema")
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Link: https://lore.kernel.org/r/20210115193218.5809-1-grygorii.strashko@ti.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>