global: Make <asm/global_data.h> include <asm/u-boot.h>

This follows the example of RISC-V where <asm/global_data.h> includes
<asm/u-boot.h> directly as "gd" includes a reference to bd_info already
and so the first must include the second anyhow. We then remove
<asm/u-boot.h> from all of the places which include references to "gd"
an so have <asm/global_data.h> already.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/powerpc/include/asm/global_data.h b/arch/powerpc/include/asm/global_data.h
index f786012..a9efbbd 100644
--- a/arch/powerpc/include/asm/global_data.h
+++ b/arch/powerpc/include/asm/global_data.h
@@ -93,4 +93,6 @@
 
 #define DECLARE_GLOBAL_DATA_PTR     register volatile gd_t *gd asm ("r2")
 
+#include <asm/u-boot.h>
+
 #endif /* __ASM_GBL_DATA_H */