efi_loader: incorrect check against FDT_ADDR_T_NONE

With commit 0d7c2913 ("cmd: bootefi: Honor the address & size cells
properties correctly") addr was replaced by fdt_addr. But not in the check
against FDT_ADDR_T_NONE.

Fixes: 0d7c2913 ("cmd: bootefi: Honor the address & size cells properties
correctly")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>