rcar_gen3: drivers: delay: Rewrite from assembler to C

Rewrite the delay code from assembler to C.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
diff --git a/plat/renesas/rcar/platform.mk b/plat/renesas/rcar/platform.mk
index 5d1f5f6..26f3c34 100644
--- a/plat/renesas/rcar/platform.mk
+++ b/plat/renesas/rcar/platform.mk
@@ -355,7 +355,7 @@
 			drivers/renesas/rcar/rpc/rpc_driver.c		\
 			drivers/renesas/rcar/dma/dma_driver.c		\
 			drivers/renesas/rcar/avs/avs_driver.c		\
-			drivers/renesas/rcar/delay/micro_delay.S	\
+			drivers/renesas/rcar/delay/micro_delay.c	\
 			drivers/renesas/rcar/emmc/emmc_interrupt.c	\
 			drivers/renesas/rcar/emmc/emmc_utility.c	\
 			drivers/renesas/rcar/emmc/emmc_mount.c		\