mmc: sdhci-msm: Initial support for Qualcomm chipsets

This platform driver adds the initial support of Secure Digital Host
Controller Interface compliant controller found in Qualcomm chipsets.

Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
Tested-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: Georgi Djakov <gdjakov@mm-sol.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>