parisc: syscalls: ignore nfsservctl for other architectures

This adds an exception to the syscall table checking script.

nfsservctl entry is only provided on x86, and there is no
reason to add it elsewhere. However, including it on the
syscall table caused a warning for most configurations on
non-x86.

<stdin>:696:2: warning: #warning syscall nfsservctl not implemented [-Wcpp]

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