clk: hisilicon: hi3519: Release the correct number of gates in hi3519_clk_unregister()

clk: hisilicon: hi3519: Release the correct number of gates in hi3519_clk_unregister()

The gates are stored in 'hi3519_gate_clks', not 'hi3519_mux_clks'.
This is also in line with how hisi_clk_register_gate() is called in the
probe.

Fixes: 224b3b262c52 ("clk: hisilicon: hi3519: add driver remove path and fix some issues")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/c3f1877c9a0886fa35c949c8f0ef25547f284f18.1704912510.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Stephen Boyd <sboyd@kernel.org>