common: Add "ifndef __ASSEMBLY__" in asm/global_data.h

Commit "common: Drop asm/global_data.h from common header" added
asm/global_data.h into secure.h. However, secure.h will be included
by psci.S. Adding asm/global_data.h has caused compilation failure in
pcsi.S. Add "ifndef __ASSEMBLY__" in asm/global_data.h.

Signed-off-by: Siew Chin Lim <elly.siew.chin.lim@intel.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/include/asm/global_data.h

@@ -7,6 +7,8 @@
 #ifndef	__ASM_GBL_DATA_H
 #define __ASM_GBL_DATA_H
 
+#ifndef __ASSEMBLY__
+
 #include <asm/types.h>
 #include <linux/types.h>
 
@@ -125,4 +127,6 @@ static inline void set_gd(volatile gd_t *gd_ptr)
 #endif
 }
 
+#endif /* __ASSEMBLY__ */
+
 #endif /* __ASM_GBL_DATA_H */