clk: at91: sam9x60-pll: add driver compatible with ccf

Add sam9x60-pll driver compatible with common clock framework.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
diff --git a/drivers/clk/at91/Kconfig b/drivers/clk/at91/Kconfig
index 8d482a2..4abc802 100644
--- a/drivers/clk/at91/Kconfig
+++ b/drivers/clk/at91/Kconfig
@@ -54,3 +54,10 @@
 	  that may be different from the system clock. This second
 	  clock is the generic clock (GCLK) and is managed by
 	  the PMC via PMC_PCR register.
+
+config AT91_SAM9X60_PLL
+	bool "PLL support for SAM9X60 SoCs"
+	depends on CLK_AT91
+	help
+	  This option is used to enable the AT91 SAM9X60's PLL clock
+	  driver.