Replace __ASSEMBLY__ with compiler-builtin __ASSEMBLER__

NOTE: __ASSEMBLY__ macro is now deprecated in favor of __ASSEMBLER__.

All common C compilers predefine a macro called __ASSEMBLER__ when
preprocessing a .S file. There is no reason for TF-A to define it's own
__ASSEMBLY__ macro for this purpose instead. To unify code with the
export headers (which use __ASSEMBLER__ to avoid one extra dependency),
let's deprecate __ASSEMBLY__ and switch the code base over to the
predefined standard.

Change-Id: Id7d0ec8cf330195da80499c68562b65cb5ab7417
Signed-off-by: Julius Werner <jwerner@chromium.org>
diff --git a/include/plat/arm/board/common/board_css_def.h b/include/plat/arm/board/common/board_css_def.h
index f982b57..4637b67 100644
--- a/include/plat/arm/board/common/board_css_def.h
+++ b/include/plat/arm/board/common/board_css_def.h
@@ -29,7 +29,7 @@
 #define BOARD_CSS_PLAT_TYPE_EMULATOR		0x02
 #define BOARD_CSS_PLAT_TYPE_FVP			0x03
 
-#ifndef __ASSEMBLY__
+#ifndef __ASSEMBLER__
 
 #include <lib/mmio.h>
 
@@ -37,7 +37,7 @@
 	((mmio_read_32(addr) & BOARD_CSS_PLAT_ID_REG_ID_MASK)		\
 	>> BOARD_CSS_PLAT_ID_REG_ID_SHIFT)
 
-#endif /* __ASSEMBLY__ */
+#endif /* __ASSEMBLER__ */
 
 
 #define MAX_IO_DEVICES			3