FROMLIST: mmc: core: Export core functions required for clk scaling

Export core function required for clk scaling post design change.
This would help make clk scaling part of vendor module.

Bug: 192337957
Link: https://lore.kernel.org/lkml/1571668177-3766-2-git-send-email-


rampraka@codeaurora.org/
Change-Id: I0c5eccb2052197b3a290f7322429cab679c5ade5
Signed-off-by: Nitin Rawat <nitirawa@codeaurora.org>
Signed-off-by: Ram Prakash Gupta <rampraka@codeaurora.org>