rtc: sun6i: Fix bit_idx value for clk_register_gate

clk-gate core will take bit_idx through clk_register_gate
and then do clk_gate_ops by using BIT(bit_idx), but rtc-sun6i
is passing bit_idx as BIT(bit_idx) it becomes BIT(BIT(bit_idx)
which is wrong and eventually external gate clock is not enabling.

This patch fixed by passing bit index and the original change
introduced from below commit.
"rtc: sun6i: Add support for the external oscillator gate"
(sha1: 	17ecd24)

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Fixes: 17ecd24 ("rtc: sun6i: Add support for the external oscillator gate")
Cc: stable@vger.kernel.org
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-sun6i.c

@@ -74,7 +74,7 @@
 #define SUN6I_ALARM_CONFIG_WAKEUP		BIT(0)
 
 #define SUN6I_LOSC_OUT_GATING			0x0060
-#define SUN6I_LOSC_OUT_GATING_EN		BIT(0)
+#define SUN6I_LOSC_OUT_GATING_EN_OFFSET		0
 
 /*
  * Get date values
@@ -255,7 +255,7 @@ static void __init sun6i_rtc_clk_init(struct device_node *node)
 				      &clkout_name);
 	rtc->ext_losc = clk_register_gate(NULL, clkout_name, rtc->hw.init->name,
 					  0, rtc->base + SUN6I_LOSC_OUT_GATING,
-					  SUN6I_LOSC_OUT_GATING_EN, 0,
+					  SUN6I_LOSC_OUT_GATING_EN_OFFSET, 0,
 					  &rtc->lock);
 	if (IS_ERR(rtc->ext_losc)) {
 		pr_crit("Couldn't register the LOSC external gate\n");