clk: sirf: add CSR atlas7 clk and reset support

the hardware node includes both clock and reset support, so it
is named as "car".
this patch implements Flexible clocks(mux, divider, gate), Selectable
clock(mux, divider, gate), root clock(gate),leaf clock(gate), others.
it also implements the reset controller functionality.

Signed-off-by: Zhiwu Song <Zhiwu.Song@csr.com>
Signed-off-by: Guo Zeng <Guo.Zeng@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>