board_f: Drop board_type parameter from initdram()

It looks like only cm5200 and tqm8xx use this feature, so we don't really
need it in generic code. Drop it and have the users access gd->board_type
directly.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/board/amcc/bamboo/bamboo.c b/board/amcc/bamboo/bamboo.c
index 2838f9a..ae69f5a 100644
--- a/board/amcc/bamboo/bamboo.c
+++ b/board/amcc/bamboo/bamboo.c
@@ -436,7 +436,7 @@
 }
 
 
-phys_size_t initdram (int board_type)
+phys_size_t initdram(void)
 {
 	return spd_sdram();
 }