This commit finally adds support for the built in SD/MMC controller in
IPQ4019 SoC.
Controller is supported by the upstream SDHCI-MSM driver with a minor
clock setting patch.
Patch is special to the IPQ4019 and cannot be upstreamed.
Patch that adds the SDHCI node is already submitted upstream.
Signed-off-by: Robert Marko <robimarko@gmail.com>