sandbox: Fix warning in display_options

This fixes a warning in the print_buffer() function with some toolchains.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>

lib/display_options.c

@@ -152,7 +152,7 @@ int print_buffer(ulong addr, const void *data, uint width, uint count,
 			else
 				x = lb.uc[i] = *(volatile uint8_t *)data;
 #ifdef CONFIG_SYS_SUPPORT_64BIT_DATA
-			printf(" %0*" PRIx64, width * 2, x);
+			printf(" %0*llx", width * 2, (long long)x);
 #else
 			printf(" %0*x", width * 2, x);
 #endif