KVM: PPC: Book3S HV: Remove kvmhv_p9_[set,restore]_lpcr declarations

The commit b1b1697a ("KVM: PPC: Book3S HV: Remove support for
running HPT guest on RPT host without mixed mode support") removed the
last references to these functions.

Fixes: b1b1697a ("KVM: PPC: Book3S HV: Remove support for running HPT guest on RPT host without mixed mode support")
Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220711223617.63625-2-muriloo@linux.ibm.com