common: Move testdram() into init.h

This function is called during init so move it to the init header file.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/socrates/sdram.c b/board/socrates/sdram.c
index 9ee6f3d..8eb4f8f 100644
--- a/board/socrates/sdram.c
+++ b/board/socrates/sdram.c
@@ -62,7 +62,7 @@
 #endif
 
 #if defined(CONFIG_SYS_DRAM_TEST)
-int testdram (void)
+int testdram(void)
 {
 	uint *pstart = (uint *) CONFIG_SYS_MEMTEST_START;
 	uint *pend = (uint *) CONFIG_SYS_MEMTEST_END;