exec: simplify the copy_strings_kernel calling convention

copy_strings_kernel is always used with a single argument,
adjust the calling convention to that.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Link: http://lkml.kernel.org/r/20200501104105.2621149-2-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index a345d9f..3d3afe0 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -144,8 +144,7 @@ extern int setup_arg_pages(struct linux_binprm * bprm,
 extern int transfer_args_to_stack(struct linux_binprm *bprm,
 				  unsigned long *sp_location);
 extern int bprm_change_interp(const char *interp, struct linux_binprm *bprm);
-extern int copy_strings_kernel(int argc, const char *const *argv,
-			       struct linux_binprm *bprm);
+int copy_string_kernel(const char *arg, struct linux_binprm *bprm);
 extern void install_exec_creds(struct linux_binprm *bprm);
 extern void set_binfmt(struct linux_binfmt *new);
 extern ssize_t read_code(struct file *, unsigned long, loff_t, size_t);