Support the V1.1 hardware revisions with the following change:

Changed power rail for MMC1 interface to a 3.3V/1.8V switchable rail in
order to be able to run UHS SD cards in ultra high speed 1.8V mode.

[  207.502011] mmc2: host does not support reading read-only switch,
 assuming write-enable
[  207.517011] mmc2: new ultra high speed SDR104 SDHC card at address
 aaaa
[  207.534190] mmcblk2: mmc2:aaaa SE32G 29.7 GiB
[  207.545096]  mmcblk2: p1

root@apalis-t30:~# cat /sys/kernel/debug/mmc2/ios
clock:          208000000 Hz
actual clock:   204000000 Hz
vdd:            21 (3.3 ~ 3.4 V)
bus mode:       2 (push-pull)
chip select:    0 (don't care)
power mode:     2 (on)
bus width:      2 (4 bits)
timing spec:    6 (sd uhs SDR104)
signal voltage: 1 (1.80 V)
driver type:    0 (driver type B)
root@apalis-t30:~# hdparm -t /dev/mmcblk2

/dev/mmcblk2:
 Timing buffered disk reads: 256 MB in  3.02 seconds =  84.71 MB/sec
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>