powerpc: Add more Power7 specific definitions

stable-2.6.27.60 added c24cb8e5 which uses PV_POWER7 but it's not
defined.  Following patch adds these definitions.

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>

commit 50fb8ebe upstream

powerpc: Add more Power7 specific definitions

This adds more SPR definitions used on newer processors when running
in hypervisor mode. Along with some other P7 specific bits and pieces

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>