arm64: kconfig: drop CONFIG_RTC_LIB dependency

BugLink: https://bugs.launchpad.net/bugs/1826212

[ Upstream commit 99a50777 ]

The rtc-lib dependency is not required, and seems it was just
copy-pasted from ARM's Kconfig. If platform requires rtc-lib,
they should select it individually.
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

arch/arm64/Kconfig

@@ -94,7 +94,6 @@ config ARM64
 	select PERF_USE_VMALLOC
 	select POWER_RESET
 	select POWER_SUPPLY
-	select RTC_LIB
 	select SPARSE_IRQ
 	select SYSCTL_EXCEPTION_TRACE
 	select HAVE_CONTEXT_TRACKING