ARM: keystone: Remove clk-provider.h include

This file doesn't use the clk provider APIs. Remove the include.

Cc: Nishanth Menon <nm@ti.com>
Cc: Sekhar Nori <nsekhar@ti.com>
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>