common/memsize.c: Fix get_effective_memsize() to always check for CONFIG_MAX_MEM_MAPPED

CONFIG_MAX_MEM_MAPPED when defined specifies upper memory mapped limit.
So check for it always, and not only when CONFIG_VERY_BIG_RAM is defined.

Signed-off-by: Pali Rohár <pali@kernel.org>
diff --git a/common/memsize.c b/common/memsize.c
index d5d13d5..31884ac 100644
--- a/common/memsize.c
+++ b/common/memsize.c
@@ -94,7 +94,7 @@
 
 phys_size_t __weak get_effective_memsize(void)
 {
-#ifndef CONFIG_VERY_BIG_RAM
+#ifndef CONFIG_MAX_MEM_MAPPED
 	return gd->ram_size;
 #else
 	/* limit stack to what we can reasonable map */