mmc: sdhci-msm: Add msm version specific ops and data structures

In addition to offsets of certain registers changing, the registers in
core_mem have been shifted to HC mem as well. To access these
registers, define msm version specific functions. These functions can
be loaded into the function pointers at the time of probe based on
the msm version detected.

Also defind new data structure to hold version specific Ops and
register addresses.

Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
Reviewed-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>