powerpc/smp: Remove unused inline functions

commit 441c19c8 ("powerpc/kvm/book3s_hv: Rework the secondary
inhibit code") left behind this, so can remove it.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210324140752.11320-1-yuehaibing@huawei.com