common: Add get_effective_memsize() to memsize.c

This function has been around for powerpc. It is used for systems with
memory more than CONFIG_MAX_MEM_MAPPED. In case of non-contiguous memory,
this feature can limit U-boot to one block without going over the limit.

Signed-off-by: York Sun <yorksun@freescale.com>
Acked-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
diff --git a/board/freescale/c29xpcie/spl.c b/board/freescale/c29xpcie/spl.c
index 3cfdb72..2111711 100644
--- a/board/freescale/c29xpcie/spl.c
+++ b/board/freescale/c29xpcie/spl.c
@@ -12,7 +12,7 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-ulong get_effective_memsize(void)
+phys_size_t get_effective_memsize(void)
 {
 	return CONFIG_SYS_L2_SIZE;
 }