ARM i.MX: fix error-valued pointer dereference in clk_register_gate2()

The error-valued pointer clk is used for the arg of kfree, it should be
kfree(gate) if clk_register() return ERR_PTR().

dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch

)

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>