clk: versatile: hide clock drivers from non-ARM users

Commit 419b3ab6 ("clk: versatile: remove dependency on ARCH_*")
made the whole menu of ARM reference clock drivers visible on all
architectures. I can't see how this is an improvement for non-ARM
users. Unless build-testing, there is no point on presenting
ARM-only clock drivers on other architectures.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20210901180953.5bd2a994@endymion


Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>