arm64: dts: ti: Disable UHS speed modes on MMCSD1 instance

Instabilities were observed on a few SD cards when UHS speed modes were
enabled. Therefore, disable UHS modes by adding the tag no-1-8-v tag, in
sdhci1 device tree node.

Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Tested-by: Bryan Brattlof <bb@ti.com>