ARM: dts: move the fixed MMC regulator to SURF board

There is currently a fixed regulator in the .dtsi file for
the MSM8660 chipset, used by the SURF board. We want to define
real regulators for a board using this chipset, so push the fixed
regulator down to the SURF board which is the only user.

Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>