Revert "parisc: implement full version of access_ok()"

Revert "parisc: implement full version of access_ok()"

This reverts commit a9ac906e1c492a5bd4f843789867497f7f2fbd39.

It broke userspace and adding more checking is not needed.
Even checking if a syscall would access memory in page zero doesn't
makes sense since it may lead to some syscalls returning -EFAULT
where we would return other error codes on other platforms.
In summary, just drop this change and return to always return 1.

Signed-off-by: Helge Deller <deller@gmx.de>