If UHS speed modes are enabled, a compatible SD card switches down to
1.8V during enumeration. If after this a software reboot/crash takes
place and on-chip ROM tries to enumerate the SD card, the difference in
IO voltages (host @ 3.3V and card @ 1.8V) may end up damaging the card.

The fix for this is to have support for power cycling the card in
hardware (with a PORz/soft-reset line causing a power cycle of the
card). Because the beaglebone X15 (rev A,B and C), am57xx-idks and
am57xx-evms don't have this capability, disable voltage switching for
these boards.

The major effect of this is that the maximum supported speed
mode is now high speed(50 MHz) down from SDR104(200 MHz).

commit 88a74841

 ("ARM: dts: am57xx-idk: Remove support for voltage
switching for SD card") did this only for idk boards. Do it for all
affected boards.

Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>