drivers/firmware/efi/efivars.c: use in_compat_syscall() to check for compat callers

This should make no difference on any architecture, as x86's historical
is_compat_task behavior really did check whether the calling syscall was
a compat syscall. x86's is_compat_task is going away, though.

Signed-off-by: Andy Lutomirski <[e-mail]>
Reviewed-by: Matt Fleming <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/firmware/efi/efivars.c

···
 
 static inline bool is_compat(void)
 {
-	if (IS_ENABLED(CONFIG_COMPAT) && is_compat_task())
+	if (IS_ENABLED(CONFIG_COMPAT) && in_compat_syscall())
 		return true;
 
 	return false;