time: Introduce CONFIG_64BIT_TIME in architectures

There are a total of 53 system calls (aside from ioctl) that pass a time_t
or derived data structure as an argument, and in order to extend time_t
to 64-bit, we have to replace them with new system calls and keep providing
backwards compatibility.

To avoid adding completely new and untested code for this purpose, we
introduce a new CONFIG_64BIT_TIME symbol. Every architecture that supports
new 64 bit time_t syscalls enables this config.

After this is done for all architectures, the CONFIG_64BIT_TIME symbol
will be deleted.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/Kconfig

@@ -870,6 +870,14 @@ config OLD_SIGACTION
 config COMPAT_OLD_SIGACTION
 	bool
 
+config 64BIT_TIME
+	def_bool ARCH_HAS_64BIT_TIME
+	help
+	  This should be selected by all architectures that need to support
+	  new system calls with a 64-bit time_t. This is relevant on all 32-bit
+	  architectures, and 64-bit architectures as part of compat syscall
+	  handling.
+
 config ARCH_NO_COHERENT_DMA_MMAP
 	bool