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/mips/mach-octeon/dram.c b/arch/mips/mach-octeon/dram.c
index 85cb084..5b1311d 100644
--- a/arch/mips/mach-octeon/dram.c
+++ b/arch/mips/mach-octeon/dram.c
@@ -77,7 +77,7 @@
 	return UBOOT_RAM_SIZE_MAX;
 }
 
-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)
 {
 	if (IS_ENABLED(CONFIG_RAM_OCTEON)) {
 		/* Map a maximum of 256MiB - return not size but address */