fs/binfmt_elf: refactor load_elf_binary function

fs/binfmt_elf: refactor load_elf_binary function

I delete load_addr because it is not used anymore.  And I rename
load_addr_set to first_pt_load because it is used only to capture the
first iteration of the loop.

Link: https://lkml.kernel.org/r/20211212232414.1402199-3-akirakawata1@gmail.com
Signed-off-by: Akira Kawata <akirakawata1@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>