lib: date_time: Replace deprecated CONFIG_POSIX_CLOCK option

Replaced CONFIG_POSIX_CLOCK option with CONFIG_POSIX_TIMERS, which
is now used to enable clock_gettime() and clock_settime() support.

Signed-off-by: Tommi Kangas <[email protected]>

Author: tokangas

lib/date_time/Kconfig

@@ -6,7 +6,7 @@
 
 menuconfig DATE_TIME
 	bool "Date time library"
-	select POSIX_CLOCK
+	select POSIX_TIMERS
 
 if DATE_TIME