powerpc: Switch to using CONFIG_SYS_INIT_SP_OFFSET from CONFIG_SYS_GBL_DATA_OFFSET

In the places where PowerPC references CONFIG_SYS_GBL_DATA_OFFSET it
does so as (CONFIG_SYS_INIT_RAM_ADDR + CONFIG_SYS_GBL_DATA_OFFSET).  And
it defines CONFIG_SYS_GBL_DATA_OFFSET in the same manner that other
architectures define CONFIG_SYS_INIT_SP_OFFSET. Other architectures
define CONFIG_SYS_INIT_SP_ADDR as (CONFIG_SYS_INIT_RAM_ADDR +
CONFIG_SYS_INIT_SP_OFFSET) typically.  Rename things within PowerPC for
consistency with other architectures.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/include/configs/T208xQDS.h b/include/configs/T208xQDS.h
index d6bb8d1..ca9ae9b 100644
--- a/include/configs/T208xQDS.h
+++ b/include/configs/T208xQDS.h
@@ -302,9 +302,8 @@
 			((CONFIG_SYS_INIT_RAM_ADDR_PHYS_HIGH * 1ull << 32) | \
 			CONFIG_SYS_INIT_RAM_ADDR_PHYS_LOW)
 #define CONFIG_SYS_INIT_RAM_SIZE	0x00004000
-#define CONFIG_SYS_GBL_DATA_OFFSET	(CONFIG_SYS_INIT_RAM_SIZE - \
-						GENERATED_GBL_DATA_SIZE)
-#define CONFIG_SYS_INIT_SP_OFFSET	CONFIG_SYS_GBL_DATA_OFFSET
+#define CONFIG_SYS_INIT_SP_OFFSET	(CONFIG_SYS_INIT_RAM_SIZE - GENERATED_GBL_DATA_SIZE)
+#define CONFIG_SYS_INIT_SP_ADDR		(CONFIG_SYS_INIT_RAM_ADDR + CONFIG_SYS_INIT_SP_OFFSET)
 #define CONFIG_SYS_MONITOR_LEN		(768 * 1024)
 
 /*