clk: Remove unused clk_hw_rate_is_protected

clk_hw_rate_is_protected() was added in 2017's commit
e55a839a ("clk: add clock protection mechanism to clk core")

but has been unused.

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://lore.kernel.org/r/20241009003552.254675-1-linux@treblig.org


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