AArch32: Add ARM platform changes in BL1

This patch adds ARM platform changes in BL1 for AArch32 state.
It also enables building of BL1 for ARCH=aarch32.

Change-Id: I079be81a93d027f37b0f7d8bb474b1252bb4cf48
diff --git a/plat/arm/board/fvp/platform.mk b/plat/arm/board/fvp/platform.mk
index 2865569..1dad989 100644
--- a/plat/arm/board/fvp/platform.mk
+++ b/plat/arm/board/fvp/platform.mk
@@ -113,8 +113,8 @@
 
 BL1_SOURCES		+=	drivers/io/io_semihosting.c			\
 				lib/semihosting/semihosting.c			\
-				lib/semihosting/aarch64/semihosting_call.S	\
-				plat/arm/board/fvp/aarch64/fvp_helpers.S	\
+				lib/semihosting/${ARCH}/semihosting_call.S	\
+				plat/arm/board/fvp/${ARCH}/fvp_helpers.S	\
 				plat/arm/board/fvp/fvp_bl1_setup.c		\
 				plat/arm/board/fvp/fvp_err.c			\
 				plat/arm/board/fvp/fvp_io_storage.c		\