overlays: Add updated mmc1 alias to sdio overlays

overlays: Add updated mmc1 alias to sdio overlays

In the downstream RPi kernel, aliases are used to assign instance
numbers to the SD/MMC interfaces. The updated sdio overlays
effectively rename the device node, so the mmc1 alias has to be
updated in order to preserve the mmc1 numbering, otherwise the device
will appear as mmc2.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>
(cherry picked from commit e947e787796e72ca7fce395a0179b63d32b8eff8
https://github.com/raspberrypi/linux raspi/rpi-4.15.y)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>