board_f: Drop return value from initdram()

At present we cannot use this function as an init sequence call without a
wrapper, since it returns the RAM size. Adjust it to set the RAM size in
global_data instead, and return 0 on success.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/board/xilinx/ppc405-generic/xilinx_ppc405_generic.c b/board/xilinx/ppc405-generic/xilinx_ppc405_generic.c
index dfdd3f2..6148a4b 100644
--- a/board/xilinx/ppc405-generic/xilinx_ppc405_generic.c
+++ b/board/xilinx/ppc405-generic/xilinx_ppc405_generic.c
@@ -10,6 +10,8 @@
 #include <common.h>
 #include <asm/processor.h>
 
+DECLARE_GLOBAL_DATA_PTR;
+
 ulong get_PCI_freq(void)
 {
 	return 0;
@@ -21,10 +23,12 @@
 	return 0;
 }
 
-phys_size_t initdram(void)
+int initdram(void)
 {
-	return get_ram_size(XPAR_DDR2_SDRAM_MEM_BASEADDR,
+	gd->ram_size = get_ram_size(XPAR_DDR2_SDRAM_MEM_BASEADDR,
 			    CONFIG_SYS_SDRAM_SIZE_MB * 1024 * 1024);
+
+	return 0;
 }
 
 void get_sys_info(sys_info_t *sys_info)