kvm: ifdef KVM_CREATE_SPAPR_TCE and KVM_ALLOCATE_RMA

Some PowerPC toolchains have an old Linux headers which don't define the
KVM_CREATE_SPAPR_TCE and KVM_ALLOCATE_RMA macros. To workaround this
problem we enclose the lines which use these macros into ifdef blocks.

Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>