drivers: counter: cc23x0: Add dependency for RTC

In case RTC is used for system timer, it should not be used
as counter device. Dependency restricts counter driver to work
only with SYSTIM.

Signed-off-by: Stoyan Bogdanov <sbogdanov@baylibre.com>

Author: bogdanovs

drivers/counter/Kconfig.cc23x0_rtc

@@ -5,5 +5,6 @@ config COUNTER_CC23X0_RTC
 	bool "CC23x0 Counter driver based on the RTC Timer"
 	default y
 	depends on DT_HAS_TI_CC23X0_RTC_ENABLED
+	depends on CC23X0_SYSTIM_TIMER
 	help
 	  Enable counter driver based on RTC timer for cc23x0