UHS-I speed modes are supported in AM65 S.R. 2.0 SoC[1].

Add support by removing the no-1-8-v tag and including the voltage
regulator device tree nodes for power cycling.

However, the 4 bit interface of AM65 SR 1.0 cannot be supported at 3.3 V or
1.8 V because of erratas i2025 and i2026 [2]. As the SD card is the primary
boot mode for development usecases, continue to enable SD card and disable
UHS-I modes in it to minimize any ageing issues happening because of
erratas.

k3-am6528-iot2050-basic and k3-am6548-iot2050-advanced boards use S.R. 1.0
version of AM65 SoC. Therefore, add no-1-8-v in sdhci1 device tree node of
the common iot2050 device tree file.

[1] - https://www.ti.com/lit/ug/spruid7e/spruid7e.pdf, section 12.3.6.1.1
[2] - https://www.ti.com/lit/er/sprz452e/sprz452e.pdfSigned-off-by: Aswath Govindraju <a-govindraju@ti.com>
Acked-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Link: https://lore.kernel.org/r/20210529033749.6250-1-a-govindraju@ti.com