Add a driver for the CPU pll/ARM pll/MIPS pll that is present
in MStar SoCs.

Currently there is no documentation for this block so it's possible
this driver isn't entirely correct.

Only tested on the version of this IP in the MStar/SigmaStar
ARMv7 SoCs.
Signed-off-by: Daniel Palmer <daniel@0x0f.com>
Co-developed-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Romain Perier <romain.perier@gmail.com>
Link: https://lore.kernel.org/r/20221022133404.3832-2-romain.perier@gmail.comSigned-off-by: Stephen Boyd <sboyd@kernel.org>