arm: mmc: Add "ti, am335-sdhci" compatible for TI's omap_hsmmc driver

In the Linux kernel (v5.16) for this SoC there are two separate drivers
- namely sdhci-omap.c and omap_hsmmc.c which have separate set of
compatibles.

The U-Boot's drivers/mmc/omap_hsmmc.c driver supports both eMMC and
SD devices - hence the compatible for SDHCI can be added.

After this change the am335x DTS description can be easier ported
from Linux kernel.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>