clk: ingenic: Include clk.h

This clock provider uses the consumer API, so include clk.h
explicitly.

Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Paul Cercueil <paul@crapouillou.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>