parisc: remove __NR_Linux from uapi header file.

The __NR_Linux defined as 0 to support HP-UX syscalls along
with an offset to other system call. But support for HP-UX
is gone and there is no need to define __NR_Linux as 0.

One of the patch in this patch series will generate uapi header
file which does have offset logic support. But here the offset
value __NR_Linux defined as 0 and it doesn't make much effect.
So remove the offset  __NR_Linux from uapi header file.

Signed-off-by: Firoz Khan <firoz.khan@linaro.org>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Helge Deller <deller@gmx.de>