ARM: at91: Remove clk-provider.h include

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

Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>