mmc: core: Use device_property_read instead of of_property_read

commit 73a47a9bb3e2c4a9c553c72456e63ab991b1a4d9 upstream.

Using the device_property interfaces allows mmc drivers to work
on platforms which run on either device tree or ACPI.

Signed-off-by: David Woods <dwoods@mellanox.com>
Reviewed-by: Chris Metcalf <cmetcalf@mellanox.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>