clocksource/drivers/st_lpc: Fix Kconfig dependency

Change the Kconfig selection rule by letting the STI arch to select
the timer.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Maxime Coquelin <maxime.coquelin@st.com>

arch/arm/mach-sti/Kconfig

@@ -3,6 +3,7 @@ menuconfig ARCH_STI
 	select ARM_GIC
 	select ST_IRQCHIP
 	select ARM_GLOBAL_TIMER
+	select CLKSRC_ST_LPC
 	select PINCTRL
 	select PINCTRL_ST
 	select MFD_SYSCON

drivers/clocksource/Kconfig

@@ -326,7 +326,6 @@ config CLKSRC_IMX_GPT
 
 config CLKSRC_ST_LPC
 	bool
-	depends on ARCH_STI
 	select CLKSRC_OF if OF
 	help
 	  Enable this option to use the Low Power controller timer