clk: msm: clock-a7: Add support for mdmcalifornium

The clock-a7 driver can support the mdmcalifornium a7
subsystem. Compile the clock-a7 driver for the same and
update the corresponding documentation accordingly.

Change-Id: I3a37ac2d0c02f9b60d26f06dc5c031104212f9bd
Signed-off-by: Devesh Jhunjhunwala <deveshj@codeaurora.org>