clk: at91: sam9x60: fix main rc oscillator frequency

Main RC oscillator frequency is 12MHz according to datasheet
(chapter 27.2).

Fixes: 01e2113d ("clk: at91: add sam9x60 pmc driver")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/1595403506-8209-8-git-send-email-claudiu.beznea@microchip.comSigned-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/at91/sam9x60.c

@@ -189,7 +189,7 @@ static void __init sam9x60_pmc_setup(struct device_node *np)
 	if (!sam9x60_pmc)
 		return;
 
-	hw = at91_clk_register_main_rc_osc(regmap, "main_rc_osc", 24000000,
+	hw = at91_clk_register_main_rc_osc(regmap, "main_rc_osc", 12000000,
 					   50000000);
 	if (IS_ERR(hw))
 		goto err_free;