xen: delete new instances of added __cpuinit

xen: delete new instances of added __cpuinit

commit 6efa20e49b9cb1db1ab66870cc37323474a75a13
("xen: Support 64-bit PV guest receiving NMIs") and
commit cd9151e26d31048b2b5e00fd02e110e07d2200c9
( "xen/balloon: set a mapping for ballooned out pages")
added new instances of __cpuinit usage.

We removed this a couple versions ago; we now want to remove
the compat no-op stubs.  Introducing new users is not what
we want to see at this point in time, as it will break once
the stubs are gone.

Cc: Konrad Rzeszutek Wilk <konrad@kernel.org>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>