binfmt_elf_fdpic: fix execfd build regression

The change to bprm->have_execfd was incomplete, leading
to a build failure:

fs/binfmt_elf_fdpic.c: In function 'create_elf_fdpic_tables':
fs/binfmt_elf_fdpic.c:591:27: error: 'BINPRM_FLAGS_EXECFD' undeclared

Change the last user of BINPRM_FLAGS_EXECFD in a corresponding
way.

Reported-by: Valdis Klētnieks <valdis.kletnieks@vt.edu>
Fixes: b8a61c9 ("exec: Generic execfd support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

fs/binfmt_elf_fdpic.c

@@ -588,7 +588,7 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 	nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) +
 		(k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
 
-	if (bprm->interp_flags & BINPRM_FLAGS_EXECFD)
+	if (bprm->have_execfd)
 		nitems++;
 
 	csp = sp;