x86: move a few device initialization objects into .devinit.rodata

Impact: debuggability and micro-optimization

Putting whatever is possible into the (final) .rodata section increases
the likelihood of catching memory corruption bugs early, and reduces
false cache line sharing.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <49B909A5.76E4.0078.0@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>