drivers/clk: Remove "select SRCU"

Now that the SRCU Kconfig option is unconditionally selected, there is
no longer any point in selecting it.  Therefore, remove the "select SRCU"
Kconfig statements.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: <linux-clk@vger.kernel.org>
Link: https://lore.kernel.org/r/20230105003813.1770367-9-paulmck@kernel.org


Signed-off-by: Stephen Boyd <sboyd@kernel.org>