clk: remove sirf prima2/atlas drivers

The CSR SiRF prima2/atlas platforms are getting removed, so this driver
is no longer needed.

Cc: Barry Song <baohua@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210120131026.1721788-4-arnd@kernel.org


Acked-by: Barry Song <baohua@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>