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/drivers/arm/gicv3.h b/include/drivers/arm/gicv3.h
index 72221ac..9c72d4d 100644
--- a/include/drivers/arm/gicv3.h
+++ b/include/drivers/arm/gicv3.h
@@ -208,7 +208,7 @@
 #define GITS_CTLR_QUIESCENT_SHIFT	31
 #define GITS_CTLR_QUIESCENT_BIT		BIT_32(GITS_CTLR_QUIESCENT_SHIFT)
 
-#ifndef __ASSEMBLY__
+#ifndef __ASSEMBLER__
 
 #include <stdbool.h>
 #include <stdint.h>
@@ -406,5 +406,5 @@
 void gicv3_clear_interrupt_pending(unsigned int id, unsigned int proc_num);
 unsigned int gicv3_set_pmr(unsigned int mask);
 
-#endif /* __ASSEMBLY__ */
+#endif /* __ASSEMBLER__ */
 #endif /* GICV3_H */