common: return type board_get_usable_ram_top

board_get_usable_ram_top() returns a physical address that is stored in
gd->ram_top. The return type of the function should be phys_addr_t like the
current type of gd->ram_top.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/arch/x86/cpu/qemu/dram.c b/arch/x86/cpu/qemu/dram.c
index 1a52d1d..d83abf0 100644
--- a/arch/x86/cpu/qemu/dram.c
+++ b/arch/x86/cpu/qemu/dram.c
@@ -72,7 +72,7 @@
  * the relocation address, and how far U-Boot is moved by relocation are
  * set in the global data structure.
  */
-phys_size_t board_get_usable_ram_top(phys_size_t total_size)
+phys_addr_t board_get_usable_ram_top(phys_size_t total_size)
 {
 	return qemu_get_low_memory_size();
 }