Map console with MM_MODE_D under hftests

When driving hftests over UART, EL1 needs direct access to the console,
i.e. not via HVCs to EL2. The corresponding MMIO pages need to be mapped
as device memory. To that end, we export the necessary stage1_locked and
mpool structs from hftest/mm.c and call plat_console_mm_init().

Change-Id: I170e391981b717d0ff787d9ef4eebe80241cfd29
diff --git a/test/hftest/ctrl_uart.c b/test/hftest/ctrl_uart.c
index da4d0d6..4bddf81 100644
--- a/test/hftest/ctrl_uart.c
+++ b/test/hftest/ctrl_uart.c
@@ -57,6 +57,9 @@
 {
 	(void)fdt;
 
+	/* Let the console driver map its memory as device memory. */
+	plat_console_mm_init(hftest_mm_get_stage1(), hftest_mm_get_ppool());
+
 	/* Initialize the console */
 	plat_console_init();