intel: mailbox: Ensure time out duration is predictive

For each count down of time out counter, wait for number of
miliseconds to ensure the time out duration is predictive.

Signed-off-by: Chee Hong Ang <chee.hong.ang@intel.com>
Change-Id: I0e92dd1ef1da0ef504ec86472cf0d3c88528930b
diff --git a/plat/intel/soc/stratix10/platform.mk b/plat/intel/soc/stratix10/platform.mk
index 3bd6af9..8bbd010 100644
--- a/plat/intel/soc/stratix10/platform.mk
+++ b/plat/intel/soc/stratix10/platform.mk
@@ -25,7 +25,8 @@
 			lib/xlat_tables/aarch64/xlat_tables.c 		\
 			lib/xlat_tables/xlat_tables_common.c 		\
 			plat/intel/soc/common/aarch64/platform_common.c \
-			plat/intel/soc/common/aarch64/plat_helpers.S
+			plat/intel/soc/common/aarch64/plat_helpers.S	\
+			plat/intel/soc/common/socfpga_delay_timer.c
 
 BL2_SOURCES     +=	\
 		common/desc_image_load.c				\
@@ -43,7 +44,6 @@
 		plat/intel/soc/stratix10/soc/s10_memory_controller.c	\
 		plat/intel/soc/stratix10/soc/s10_pinmux.c		\
                 plat/intel/soc/common/bl2_plat_mem_params_desc.c	\
-		plat/intel/soc/common/socfpga_delay_timer.c		\
 		plat/intel/soc/common/socfpga_image_load.c		\
 		plat/intel/soc/common/socfpga_storage.c			\
 		plat/intel/soc/common/soc/socfpga_emac.c		\