ARM: bcm2835: Fix integer overflow in rpi_firmware_print_firmware_revision()

time64_t is 64-bit width type, we are not supposed to supply lesser ones
as in the case of rpi_firmware_print_firmware_revision() after the commit
4a60f58e ("ARM: bcm2835: Switch to use %ptT"). Use temporary variable
of time64_t type to correctly handle lesser types.

Fixes: 4a60f58e ("ARM: bcm2835: Switch to use %ptT")
Reported-by: Stefan Wahren <wahrenst@gmx.net>
Reported-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Revieved-by: Petr Mladek <pmladek@suse.com>
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Link: https://lore.kernel.org/r/20200616163139.4229-1-andriy.shevchenko@linux.intel.com

drivers/firmware/raspberrypi.c

@@ -181,6 +181,7 @@ EXPORT_SYMBOL_GPL(rpi_firmware_property);
 static void
 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
 {
+	time64_t date_and_time;
 	u32 packet;
 	int ret = rpi_firmware_property(fw,
 					RPI_FIRMWARE_GET_FIRMWARE_REVISION,
@@ -189,7 +190,9 @@ rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
 	if (ret)
 		return;
 
-	dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &packet);
+	/* This is not compatible with y2038 */
+	date_and_time = packet;
+	dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time);
 }
 
 static void