clk: qcom: add EBI2 clocks to the MSM8660 GCC

This adds the EBI2 2X and EBI2 clocks to the MSM8660/APQ8060
GCC. This is necessary to enable clocking of the external bus
interface so that peripherals on it can be mounted. These two
clocks are simple gated branch clocks.

In the vendor tree clock-8x60, these clocks have some kind of
dependency, the EBI2 clock has .depends = &ebi2_2x_clk.c,
what this means is undocumented, it doesn't seem like there
is a parent/child relationship, so the solution I chose was to
just have the EBI2 driver get and enable both clocks.

Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>