clk: scmi: use devm_of_clk_add_hw_provider() API and drop scmi_clocks_remove

Commit aa795c41 ("clk: Add devm_of_clk_add_hw_provider()/del_provider()
APIs") adds devm_of_clk_add_hw_provider which takes care of deleting the
clock provider when the clock providers device is removed.

This patch makes use of devm_of_clk_add_hw_provider() instead of
of_clk_add_hw_provider() so that we can eliminate the need of explicit
scmi_clocks_remove for just doing of_clk_del_provider()

Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>