clk: mmp: add spin lock for clk-frac

The register used by clk-frac may be shared with
other clocks.
So it needs to use spin lock to protect the register
access.

Signed-off-by: Chao Xie <chao.xie@marvell.com>
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com>
Signed-off-by: Michael Turquette <mturquette@linaro.org>

drivers/clk/mmp/clk-mmp2.c

@@ -191,7 +191,7 @@ void __init mmp2_clk_init(void)
 	clk = mmp_clk_register_factor("uart_pll", "pll1_4", 0,
 				mpmu_base + MPMU_UART_PLL,
 				&uart_factor_masks, uart_factor_tbl,
-				ARRAY_SIZE(uart_factor_tbl));
+				ARRAY_SIZE(uart_factor_tbl), &clk_lock);
 	clk_set_rate(clk, 14745600);
 	clk_register_clkdev(clk, "uart_pll", NULL);