parisc: document the shadow registers
parisc: document the shadow registers

Signed-off-by: Helge Deller <5b1e7895819cf7d6bc77091b09bbfd6d330a4e74@gmx.de>
Cc: <4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org> # 3.10

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs